Commits · 0day-ci/linux

Historically simple-panel had code to make sure that if prepare() was called on an already-prepared panel that it was a no-op. Similarly if unprepare() was called on an already-unprepared panel it was also a no-op. Essentially it means that these functions always "forced" the value to be whatever the caller wanted it to be. You can see that the forcing behavior dates back at least as far as 2014 by looking at commit 613a633 ("drm/panel: simple: Add proper definition for prepare and unprepare"). Apparently the code supporting the historical behavior may not be needed [1] and prepare() / unprepare() are supposed to be balanced. Let's try removing it and see if anyone breaks! If they do then we can have a debate about whether we should change that code or revert this patch. :-) If nobody breaks then we've nicely saved a few lines of code and some complexity. [1] https://lore.kernel.org/r/YHePsQgqOau1V5lD@pendragon.ideasonboard.com Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Adding this link allows the panel code to do things like read the EDID. Signed-off-by: Douglas Anderson <dianders@chromium.org>

This is really just a revert of commit 58074b0 ("drm/bridge: ti-sn65dsi86: Read EDID blob over DDC"), resolving conflicts. The old code failed to read the EDID properly in a very important case: before the bridge's pre_enable() was called. The way things need to work: 1. Read the EDID. 2. Based on the EDID, decide on video settings and pixel clock. 3. Enable the bridge w/ the desired settings. The way things were working: 1. Try to read the EDID but fail; fall back to hardcoded values. 2. Based on hardcoded values, decide on video settings and pixel clock. 3. Enable the bridge w/ the desired settings. 4. Try again to read the EDID, it works now! 5. Realize that the hardcoded settings weren't quite right. 6. Disable / reenable the bridge w/ the right settings. The reasons for the failures were twofold: a) Since we never ran the bridge chip's pre-enable then we never set the bit to ignore HPD. This meant the bridge chip didn't even _try_ to go out on the bus and communicate with the panel. b) Even if we fixed things to ignore HPD, the EDID still wouldn't read if the panel wasn't on. Instead of reverting the code, we could fix it to set the HPD bit and also power on the panel. However, it also works nicely to just let the panel code read the EDID. Now that we've split the driver up we can expose the DDC AUX channel bus to the panel node. The panel can take charge of reading the EDID. NOTE: in order for things to work, anyone that needs to read the EDID will need to add something that looks like this to their panel in the dts: ddc-i2c-bus = <&sn65dsi86_bridge>; Presumably it's OK to land this without waiting for users to add the dts property since the EDID reading was a bit broken anyway, was "recently" added, and we know we must have the fallback mode to use (since the EDID reading was a bit broken). Suggested-by: Andrzej Hajda <a.hajda@samsung.com> Signed-off-by: Douglas Anderson <dianders@chromium.org>

It doesn't make sense to go out to the bus and read the EDID over and over again. Let's cache it and throw away the cache when we turn power off from the panel. Autosuspend means that even if there are several calls to read the EDID before we officially turn the power on then we should get good use out of this cache. Signed-off-by: Douglas Anderson <dianders@chromium.org>

I don't believe that it ever makes sense to read the EDID when a panel is not powered and the powering on of the panel is the job of prepare(). Let's make sure that this happens before we try to read the EDID. We use the pm_runtime functions directly rather than directly calling the normal prepare() function because the pm_runtime functions are definitely refcounted whereas it's less clear if the prepare() one is. NOTE: I'm not 100% sure how EDID reading was working for folks in the past, but I can only assume that it was failing on the initial attempt and then working only later. This patch, presumably, will fix that. If some panel out there really can read the EDID without powering up and it's a big advantage to preserve the old behavior we can add a per-panel flag. It appears that providing the DDC bus to the panel in the past was somewhat uncommon in any case. Signed-off-by: Douglas Anderson <dianders@chromium.org>

…_property() As of commit 5186421 ("drm: Introduce epoch counter to drm_connector") the drm_get_edid() function calls drm_connector_update_edid_property() for us. There's no reason for us to call it again. Signed-off-by: Douglas Anderson <dianders@chromium.org>

The of_find_i2c_adapter_by_node() could end up failing to find an adapter in certain conditions. Specifically it's possible that of_dev_or_parent_node_match() could end up finding an I2C client in the list and cause bus_find_device() to stop early even though an I2C adapter was present later in the list. Let's move the i2c_verify_adapter() into the predicate function to prevent this. Now we'll properly skip over the I2C client and be able to find the I2C adapter. This issue has always been a potential problem if a single device tree node could represent both an I2C client and an adapter. I believe this is a sane thing to do if, for instance, an I2C-connected DP bridge chip is present. The bridge chip is an I2C client but it can also provide an I2C adapter (DDC tunneled over AUX channel). We don't want to have to create a sub-node just so a panel can link to it with the "ddc-i2c-bus" property. I believe that this problem got worse, however, with commit e814e68 ("i2c: of: Try to find an I2C adapter matching the parent"). Starting at that commit it would be even easier to accidentally miss finding the adapter. Signed-off-by: Douglas Anderson <dianders@chromium.org>

We'd like to be able to expose the DDC-over-AUX channel bus to our panel. This gets into a chicken-and-egg problem because: - The panel wants to get its DDC at probe time. - The ti-sn65dsi86 MIPI-to-eDP bridge code, which provides the DDC bus, wants to get the panel at probe time. By using a sub device we can fully create the AUX channel bits so that the panel can get them. Then the panel can finish probing and the bridge can probe. To accomplish this, we also move registering the AUX channel out of the bridge's attach code and do it right at probe time. We use devm to manage cleanup. NOTE: there's a little bit of a trick here. Though the AUX channel can run without the MIPI-to-eDP bits of the code, the MIPI-to-eDP bits can't run without the AUX channel. We could come up a complicated signaling scheme (have the MIPI-to-eDP bits return EPROBE_DEFER for a while or wait on some sort of completion), but it seems simple enough to just not even bother creating the bridge device until the AUX channel probes. That's what we'll do. Signed-off-by: Douglas Anderson <dianders@chromium.org>

Let's reorganize how we init and turn on the reference clock in the code to allow us to turn it on early (even before pre_enable()) so that we can read the EDID early. This is handy for eDP because: - We always assume that a panel is there. - Once we report that a panel is there we get asked to read the EDID. - Pre-enable isn't called until we know what pixel clock we want to use and we're ready to turn everything on. That's _after_ we get asked to read the EDID. NOTE: the above only works out OK if we "refclk" is provided. Though I don't have access to any hardware that uses ti-sn65dsi86 and _doesn't_ provide a "refclk", I believe that we'll have trouble reading the EDID at bootup in that case. Specifically I believe that if there's no "refclk" we need the MIPI source clock to be active before we can successfully read the EDID. My evidence here is that, in testing, I couldn't read the EDID until I turned on the DPPLL in the bridge chip and that the DPPLL needs the input clock to be active. Since this is hard to support, let's punt trying to handle this case if there's no "refclk". In that case we'll enable comms in pre_enable() like we always did. I don't believe there are any users of the ti-sn65dsi86 bridge chip that _don't_ use "refclk". The bridge chip is _very_ inflexible in that mode. The only time I've seen that mode used was for some really early prototype hardware that was thrown in the e-waste bin years ago when we realized how inflexible it was. Even if someone is using the bridge chip without the "refclk" they're in no worse shape than they were before the (fairly recent) commit 58074b0 ("drm/bridge: ti-sn65dsi86: Read EDID blob over DDC"). Signed-off-by: Douglas Anderson <dianders@chromium.org>

No functional changes--this just makes the diffstat of a future change easier to understand. Signed-off-by: Douglas Anderson <dianders@chromium.org>

Let's make the bridge use autosuspend with a 500ms delay. This is in preparation for promoting DP AUX transfers to their own sub-driver so that we're not constantly powering up and down the device as we transfer all the chunks. Signed-off-by: Douglas Anderson <dianders@chromium.org>

When I added support for the hpd-gpio to simple-panel in commit 48834e6 ("drm/panel-simple: Support hpd-gpios for delaying prepare()"), I added a special case to handle a circular dependency I was running into on the ti-sn65dsi86 bridge chip. On my board the hpd-gpio is actually provided by the bridge chip. That was causing some circular dependency problems that I had to work around by getting the hpd-gpio late. I've now reorganized the ti-sn65dsi86 bridge chip driver to be a collection of sub-drivers. Now the GPIO part can probe separately and that breaks the chain. Let's get rid of the old code to clean things up. Signed-off-by: Douglas Anderson <dianders@chromium.org>

…drivers Let's use the newly minted aux bus to break up the driver into sub drivers. We're not doing a full breakup here: all the code is still in the same file and remains largely untouched. The big goal here of using sub-drivers is to allow part of our code to finish probing even if some other code needs to defer. This can solve some chicken-and-egg problems. Specifically: - In commit 48834e6 ("drm/panel-simple: Support hpd-gpios for delaying prepare()") we had to add a bit of a hack to simpel-panel to support HPD showing up late. We can get rid of that hack now since the GPIO part of our driver can finish probing early. - We have a desire to expose our DDC bus to simple-panel (and perhaps to a backlight driver?). That will end up with the same chicken-and-egg problem. A future patch to move this to a sub-driver will fix it. - If/when we support the PWM functionality present in the bridge chip for a backlight we'll end up with another chicken-and-egg problem. If we allow the PWM to be a sub-driver too then it solves this problem. Signed-off-by: Douglas Anderson <dianders@chromium.org>

This is just code motion of the probe routine to move all the things that are for the "whole chip" (instead of the GPIO parts or the MIPI-to-eDP parts) together at the start of probe. This is in preparation for breaking the driver into sub-drivers. Since we're using devm for all of the "whole chip" stuff this is actually quite easy now. Signed-off-by: Douglas Anderson <dianders@chromium.org>

There's no devm_runtime_enable(), but it's easy to use devm_add_action_or_reset() and means we don't need to worry about the disable in our remove() routine or in error paths. No functional changes intended by this change. Signed-off-by: Douglas Anderson <dianders@chromium.org>

Let's: - Set the drvdata as soon as it's allocated. This just sets up a pointer so there's no downside here. - Remove the useless call to i2c_set_clientdata() which is literally the same thing as dev_set_drvdata(). No functional changes intended. Signed-off-by: Douglas Anderson <dianders@chromium.org>

Tiny cleanup for probe so we don't keep having to specify "&client->dev" or "pdata->dev". No functional changes intended. Signed-off-by: Douglas Anderson <dianders@chromium.org>

Let's cleanup the debugfs code to: - Check for errors. - Use devm to manage freeing, which also means we don't need to store a pointer in our structure. Signed-off-by: Douglas Anderson <dianders@chromium.org>

Like the previous patch ("drm/bridge: ti-sn65dsi86: Rename the main driver data structure") this is just a no-op rename in preparation for splitting the driver up a bit. Here I've attempted to rename functions / structures making sure that anything applicable to the whole chip (instead of just the MIPI to eDP bridge part) included "sn65dsi86" somewhere in the name instead of just "ti_sn_bridge". Signed-off-by: Douglas Anderson <dianders@chromium.org>

In preparation for splitting this driver into sub-drivers, let's rename the main data structure so it's clear that it's holding data for the whole device and not just the MIPI-eDP bridge part. This is a no-op change. Signed-off-by: Douglas Anderson <dianders@chromium.org>

…/ prepare Unpreparing and re-preparing a panel can be a really heavy operation. Panels datasheets often specify something on the order of 500ms as the delay you should insert after turning off the panel before turning it on again. In addition, turning on a panel can have delays on the order of 100ms - 200ms before the panel will assert HPD (AKA "panel ready"). The above means that we should avoid turning a panel off if we're going to turn it on again shortly. The above becomes a problem when we want to read the EDID of a panel. The way that ordering works is that userspace wants to read the EDID of the panel _before_ fully enabling it so that it can set the initial mode correctly. However, we can't read the EDID until we power it up. This leads to code that does this dance (like ps8640_bridge_get_edid()): 1. When userspace requests EDID / the panel modes (through an ioctl), we power on the panel just enough to read the EDID and then power it off. 2. Userspace then turns the panel on. There's likely not much time between step #1 and #2 and so we want to avoid powering the panel off and on again between those two steps. Let's use Runtime PM to help us. We'll move the existing prepare() and unprepare() to be runtime resume() and runtime suspend(). Now when we want to prepare() or unprepare() we just increment or decrement the refcount. We'll default to a 1 second autosuspend delay which seems sane given the typical delays we see for panels. A few notes: - It seems the existing unprepare() and prepare() are defined to be no-ops if called extra times. We'll preserve that behavior but may try to remove it in a future patch. - This is a slight change in the ABI of simple panel. If something was absolutely relying on the unprepare() to happen instantly that simply won't be the case anymore. I'm not aware of anyone relying on that behavior, but if there is someone then we'll need to figure out how to enable (or disable) this new delayed behavior selectively. - In order for this to work we now have a hard dependency on "PM". From memory this is a legit thing to assume these days and we don't have to find some fallback to keep working if someone wants to build their system without "PM". Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210402152701.v3.12.I9e8bd33b49c496745bfac58ea9ab418bd3b6f5ce@changeid Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

If we just leave the detect() function as NULL then the upper layers assume we're always connected. There's no reason for a stub. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

We prepared the panel in pre_enable() so we should unprepare it in post_disable() to match. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Let's make the remove() function strictly the reverse of the probe() function so it's easier to reason about. This patch was created by code inspection and should move us closer to a proper remove. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

A random comment inside a function had "/**" in front of it. That doesn't make sense. Remove. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

The clock framework makes it simple to deal with an optional clock. You can call clk_get_optional() and if the clock isn't specified it'll just return NULL without complaint. It's valid to pass NULL to enable/disable/prepare/unprepare. Let's make use of this to simplify things a tiny bit. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Robert Foss <robert.foss@linaro.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>

The drm_bridge_chain_pre_enable() is not the proper opposite of drm_bridge_chain_post_disable(). It continues along the chain to _before_ the starting bridge. Let's fix that. Fixes: 05193dc ("drm/bridge: Make the bridge chain a double-linked list") Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Yuri Norov says: If parameter size is the same for native and compat ABIs, we may wire a syscall made by compat client to native handler. This is true for unsigned int, but not true for unsigned long or pointer. That's why I suggest using unsigned int and so avoid creating compat entry point. Use unsigned int as the type of the flags parameter in memfd_secret() system call. Link: https://lkml.kernel.org/r/20210331142345.27532-1-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Yury Norov <yury.norov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

The test verifies that file descriptor created with memfd_secret does not allow read/write operations, that secret memory mappings respect RLIMIT_MEMLOCK and that remote accesses with process_vm_read() and ptrace() to the secret memory fail. Link: https://lkml.kernel.org/r/20210303162209.8609-10-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Bottomley <jejb@linux.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tycho Andersen <tycho@tycho.ws> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Yuri Norov says: If parameter size is the same for native and compat ABIs, we may wire a syscall made by compat client to native handler. This is true for unsigned int, but not true for unsigned long or pointer. That's why I suggest using unsigned int and so avoid creating compat entry point. Use unsigned int as the type of the flags parameter in memfd_secret() system call. Link: https://lkml.kernel.org/r/20210331142345.27532-1-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Yury Norov <yury.norov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Wire up memfd_secret system call on architectures that define ARCH_HAS_SET_DIRECT_MAP, namely arm64, risc-v and x86. Link: https://lkml.kernel.org/r/20210303162209.8609-9-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christopher Lameter <cl@linux.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Bottomley <jejb@linux.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tycho Andersen <tycho@tycho.ws> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

It is unsafe to allow saving of secretmem areas to the hibernation snapshot as they would be visible after the resume and this essentially will defeat the purpose of secret memory mappings. Prevent hibernation whenever there are active secret memory users. Link: https://lkml.kernel.org/r/20210303162209.8609-8-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Bottomley <jejb@linux.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tycho Andersen <tycho@tycho.ws> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Yuri Norov says: If parameter size is the same for native and compat ABIs, we may wire a syscall made by compat client to native handler. This is true for unsigned int, but not true for unsigned long or pointer. That's why I suggest using unsigned int and so avoid creating compat entry point. Use unsigned int as the type of the flags parameter in memfd_secret() system call. Link: https://lkml.kernel.org/r/20210331142345.27532-1-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Yury Norov <yury.norov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Commits on Apr 16, 2021