FB: Misc waveform mode shenanigans (#1524)

* framebuffer: Misc waveform mode shenanigans on mxcfb & sunxi:
  * Support asking for A2 explicitly, since we no longer use it for fast anywhere
  * Unify the logic behind FORCE_MONOCHROME usage (i.e., only use it for DU when it's hardware-accelerated), because it makes sense to make text highlights look better (especially on high density screens). Added comments explaining the behavior a bit.
  * Support toggling NO_MERGE on a per-update basis, because of course I managed to find a case where the collision handling issues in the Sage kernel led to visible issues.
* rtc: Also log the rtc clock when validating an alarm (and switch to threadsafe functions to ensure the pointers we keep around point to our own data, and not the libc's statis storage).

ffi-cdecl/rtc_cdecl.c

@@ -18,7 +18,9 @@ cdecl_type(time_t)
 cdecl_struct(tm)
 cdecl_func(time)
 cdecl_func(gmtime)
+cdecl_func(gmtime_r)
 cdecl_func(localtime)
+cdecl_func(localtime_r)
 cdecl_func(timegm)
 cdecl_func(mktime)
 cdecl_func(settimeofday)

ffi/framebuffer.lua

@@ -145,9 +145,7 @@ function fb:init()
     if self.screen_size.w > self.screen_size.h and self.is_always_portrait then
         self.screen_size.w, self.screen_size.h = self.screen_size.h, self.screen_size.w
         -- some framebuffers need to be rotated counter-clockwise (they start in landscape mode)
-        io.flush()
         io.write("FB: Enforcing portrait mode by doing an initial BB rotation\n")
-        io.flush()
         self.debug("FB: This prevents the use of blitting optimizations. This should instead be fixed on the device's side on startup.")
         self.bb:rotate(-90)
         self.blitbuffer_rotation_mode = self.bb:getRotation()
@@ -172,28 +170,31 @@ function fb:refreshFullImp(x, y, w, h, d)
     -- the others default to fall back to this.
 end
 function fb:refreshPartialImp(x, y, w, h, d)
-    -- default is fallback
     return self:refreshFullImp(x, y, w, h, d)
 end
+function fb:refreshNoMergePartialImp(x, y, w, h, d)
+    return self:refreshPartialImp(x, y, w, h, d)
+end
 function fb:refreshFlashPartialImp(x, y, w, h, d)
-    -- default is fallback
     return self:refreshFullImp(x, y, w, h, d)
 end
 function fb:refreshUIImp(x, y, w, h, d)
-    -- default is fallback
     return self:refreshPartialImp(x, y, w, h, d)
 end
+function fb:refreshNoMergeUIImp(x, y, w, h, d)
+    return self:refreshUIImp(x, y, w, h, d)
+end
 function fb:refreshFlashUIImp(x, y, w, h, d)
-    -- default is fallback
     return self:refreshFullImp(x, y, w, h, d)
 end
 function fb:refreshFastImp(x, y, w, h, d)
-    -- default is fallback
     return self:refreshPartialImp(x, y, w, h, d)
 end
+function fb:refreshA2Imp(x, y, w, h, d)
+    return self:refreshFastImp(x, y, w, h, d)
+end
 function fb:refreshWaitForLastImp()
     -- default is NOP
-    return
 end
 
 -- these should not be overridden, they provide the external refresh API:
@@ -205,6 +206,10 @@ function fb:refreshPartial(x, y, w, h, d)
     x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
     return self:refreshPartialImp(x, y, w, h, d)
 end
+function fb:refreshNoMergePartial(x, y, w, h, d)
+    x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
+    return self:refreshNoMergePartialImp(x, y, w, h, d)
+end
 function fb:refreshFlashPartial(x, y, w, h, d)
     x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
     return self:refreshFlashPartialImp(x, y, w, h, d)
@@ -213,6 +218,10 @@ function fb:refreshUI(x, y, w, h, d)
     x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
     return self:refreshUIImp(x, y, w, h, d)
 end
+function fb:refreshNoMergeUI(x, y, w, h, d)
+    x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
+    return self:refreshNoMergeUIImp(x, y, w, h, d)
+end
 function fb:refreshFlashUI(x, y, w, h, d)
     x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
     return self:refreshFlashUIImp(x, y, w, h, d)
@@ -221,6 +230,10 @@ function fb:refreshFast(x, y, w, h, d)
     x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
     return self:refreshFastImp(x, y, w, h, d)
 end
+function fb:refreshA2(x, y, w, h, d)
+    x, y, w, h = self:calculateRealCoordinates(x, y, w, h)
+    return self:refreshA2Imp(x, y, w, h, d)
+end
 function fb:refreshWaitForLast()
     return self:refreshWaitForLastImp()
 end

ffi/framebuffer_mxcfb.lua

@@ -93,13 +93,6 @@ function framebuffer:_isNightREAGL()
    return self.night_is_reagl
 end
 
--- Returns true if waveform_mode arg matches the fast waveform mode for the current device
--- NOTE: This is to avoid explicit comparison against device-specific waveform constants in mxc_update()
---       Here, it's because some devices use A2, while other prefer DU
-function framebuffer:_isFastWaveFormMode(waveform_mode)
-    return waveform_mode == self.waveform_fast
-end
-
 -- Returns true if waveform_mode arg matches the partial waveform mode for the current device
 -- NOTE: This is to avoid explicit comparison against device-specific waveform constants in mxc_update()
 --       Here, because of REAGL or device-specific quirks.
@@ -410,8 +403,16 @@ local function refresh_k51(fb, is_flashing, waveform_mode, x, y, w, h)
         fb.update_data.hist_gray_waveform_mode = waveform_mode
     end
 
-    -- Enable the appropriate flag when requesting a 2bit update
-    if waveform_mode == C.WAVEFORM_MODE_A2 or waveform_mode == C.WAVEFORM_MODE_DU then
+    -- NOTE: Enable the appropriate flag when requesting an any->2bit update.
+    -- Since we mainly use DU for highlights, the color decimation quantization will effectively crush antialiasing on text,
+    -- avoiding making the text look fuzzy during the refresh (it'll instead look blockier, because of the lack of AA).
+    -- The higher density the screen is, the better this approach will look vs. fuzzy refresh artifacts ;).
+    -- In the very few cases we use A2 (i.e., the keyboard), using FORCE_MONOCHROME would be actively harmful:
+    -- we only highlight a border around the key, so we don't actually modify the glyph;
+    -- since non-GC updates leave untouched pixels alone, we leave the glyph (and its AA!) alone.
+    -- If we used FORCE_MONOCHROME, it would affect the whole rectangle, crushing the AA,
+    -- and the A2 update would have to pick up the modified pixels, leading to worse results.
+    if waveform_mode == C.WAVEFORM_MODE_DU then
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
@@ -446,13 +447,12 @@ local function refresh_zelda(fb, is_flashing, waveform_mode, x, y, w, h, dither)
     -- Enable the REAGLD algo when requested
     if waveform_mode == C.WAVEFORM_MODE_ZELDA_GLD16 then
         fb.update_data.flags = C.EPDC_FLAG_USE_ZELDA_REGAL
-    -- Enable the appropriate flag when requesting a 2bit update, provided we're not dithering.
-    elseif waveform_mode == C.WAVEFORM_MODE_ZELDA_A2 and not dither then
+    -- Enable the appropriate flag when requesting an any->2bit update, provided we're not dithering.
+    elseif waveform_mode == C.WAVEFORM_MODE_DU and not dither then
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
     end
-    -- TODO: There's also the HW-backed NightMode which should be somewhat accessible...
 
     return mxc_update(fb, C.MXCFB_SEND_UPDATE_ZELDA, fb.update_data, is_flashing, waveform_mode, x, y, w, h, dither)
 end
@@ -483,13 +483,12 @@ local function refresh_rex(fb, is_flashing, waveform_mode, x, y, w, h, dither)
     -- Enable the REAGLD algo when requested
     if waveform_mode == C.WAVEFORM_MODE_ZELDA_GLD16 then
         fb.update_data.flags = C.EPDC_FLAG_USE_ZELDA_REGAL
-    -- Enable the appropriate flag when requesting a 2bit update, provided we're not dithering.
-    elseif waveform_mode == C.WAVEFORM_MODE_ZELDA_A2 and not dither then
+    -- Enable the appropriate flag when requesting an any->2bit update, provided we're not dithering.
+    elseif waveform_mode == C.WAVEFORM_MODE_DU and not dither then
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
     end
-    -- TODO: There's also the HW-backed NightMode which should be somewhat accessible...
 
     return mxc_update(fb, C.MXCFB_SEND_UPDATE_REX, fb.update_data, is_flashing, waveform_mode, x, y, w, h, dither)
 end
@@ -505,9 +504,9 @@ local function refresh_mtk(fb, is_flashing, waveform_mode, x, y, w, h, dither)
         fb.update_data.hist_gray_waveform_mode = C.MTK_WAVEFORM_MODE_GC16 -- NOTE: GC16_FAST points to GC16
     end
 
-    -- Enable the appropriate flag when requesting a 2bit update, provided we're not dithering.
+    -- Enable the appropriate flag when requesting an any->2bit update, provided we're not dithering.
     -- NOTE: See FBInk note about DITHER + MONOCHROME
-    if waveform_mode == C.MTK_WAVEFORM_MODE_A2 and not dither then
+    if waveform_mode == C.MTK_WAVEFORM_MODE_DU and not dither then
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
@@ -577,8 +576,8 @@ local function refresh_kobo(fb, is_flashing, waveform_mode, x, y, w, h)
     -- Enable the appropriate flag when requesting a REAGLD waveform (WAVEFORM_MODE_REAGLD on the Aura)
     if waveform_mode == C.WAVEFORM_MODE_REAGLD then
         fb.update_data.flags = C.EPDC_FLAG_USE_AAD
-    elseif waveform_mode == C.WAVEFORM_MODE_A2 or waveform_mode == C.WAVEFORM_MODE_DU then
-        -- As well as when requesting a 2bit waveform
+    elseif waveform_mode == C.WAVEFORM_MODE_DU then
+        -- As well as when requesting an any->2bit waveform
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
@@ -600,14 +599,13 @@ local function refresh_kobo_mk7(fb, is_flashing, waveform_mode, x, y, w, h, dith
         fb.update_data.dither_mode = C.EPDC_FLAG_USE_DITHERING_PASSTHROUGH
         fb.update_data.quant_bit = 0
     end
-    -- Enable the appropriate flag when requesting a 2bit update, provided we're not dithering.
+    -- Enable the appropriate flag when requesting an any->2bit update, provided we're not dithering.
     -- NOTE: As of right now (FW 4.9.x), WAVEFORM_MODE_GLD16 appears not to be used by Nickel,
     --       so we don't have to care about EPDC_FLAG_USE_REGAL
-    -- NOTE: We never actually request A2 updates anymore (on any platform, actually), but,
+    -- NOTE: We barely ever actually request A2 updates anymore (on any platform, actually), but,
     --       on Mk. 7 specifically, we want to avoid stacking EPDC_FLAGs,
     --       because the kernel is buggy (c.f., https://github.com/NiLuJe/FBInk/blob/96a2cd6a93f5184c595c0e53a844fd883adfd75b/fbink.c#L2422-L2440).
-    --       For our use-cases, FORCE_MONOCHROME is mostly unnecessary anyway (the effect being fuzzier text instead of blockier text, i.e., choose your poison ;p).
-    if waveform_mode == C.WAVEFORM_MODE_A2 and not dither then
+    if waveform_mode == C.WAVEFORM_MODE_DU and not dither then
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
@@ -622,8 +620,8 @@ local function refresh_pocketbook(fb, is_flashing, waveform_mode, x, y, w, h)
     -- Enable the appropriate flag when requesting a REAGLD waveform (EPDC_WFTYPE_AAD on PB631)
     if waveform_mode == C.EPDC_WFTYPE_AAD then
         fb.update_data.flags = C.EPDC_FLAG_USE_AAD
-    elseif waveform_mode == C.WAVEFORM_MODE_A2 or waveform_mode == C.WAVEFORM_MODE_DU then
-        -- As well as when requesting a 2bit waveform
+    elseif waveform_mode == C.WAVEFORM_MODE_DU then
+        -- As well as when requesting an any->2bit waveform
         --- @note: Much like on rM, it appears faking 24°C instead of relying on ambient temp leads to lower latency
         fb.update_data.temp = 24
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
@@ -648,7 +646,7 @@ local function refresh_sony_prstux(fb, is_flashing, waveform_mode, x, y, w, h)
 end
 
 local function refresh_cervantes(fb, is_flashing, waveform_mode, x, y, w, h)
-    if waveform_mode == C.WAVEFORM_MODE_A2 or waveform_mode == C.WAVEFORM_MODE_DU then
+    if waveform_mode == C.WAVEFORM_MODE_DU then
         fb.update_data.flags = C.EPDC_FLAG_FORCE_MONOCHROME
     else
         fb.update_data.flags = 0
@@ -689,6 +687,11 @@ function framebuffer:refreshFastImp(x, y, w, h, dither)
     self:mech_refresh(false, self.waveform_fast, x, y, w, h, dither)
 end
 
+function framebuffer:refreshA2Imp(x, y, w, h, dither)
+    self.debug("refresh: A2", x, y, w, h, dither and "w/ HW dithering")
+    self:mech_refresh(false, self.waveform_a2, x, y, w, h, dither)
+end
+
 function framebuffer:refreshWaitForLastImp()
     if self.mech_wait_update_complete and self.dont_wait_for_marker ~= self.marker then
         self.debug("refresh: waiting for previous update", self.marker)
@@ -714,7 +717,8 @@ function framebuffer:init()
         self.mech_wait_update_complete = kindle_pearl_mxc_wait_for_update_complete
         self.mech_wait_update_submission = kindle_mxc_wait_for_update_submission
 
-        self.waveform_fast = C.WAVEFORM_MODE_A2 -- NOTE: Mostly here for archeological purposes, we switch to DU on every device right below this ;).
+        self.waveform_a2 = C.WAVEFORM_MODE_A2
+        self.waveform_fast = C.WAVEFORM_MODE_DU
         self.waveform_ui = C.WAVEFORM_MODE_GC16_FAST
         self.waveform_flashui = self.waveform_ui
         self.waveform_full = C.WAVEFORM_MODE_GC16
@@ -744,6 +748,7 @@ function framebuffer:init()
                 self.mech_refresh = refresh_rex
             end
 
+            self.waveform_a2 = C.WAVEFORM_MODE_ZELDA_A2
             self.waveform_fast = C.WAVEFORM_MODE_DU
             self.waveform_ui = C.WAVEFORM_MODE_AUTO
             -- NOTE: Possibly to bypass the possibility that AUTO, even when FULL, might not flash (something which holds true for a number of devices, especially on small regions),
@@ -767,6 +772,7 @@ function framebuffer:init()
         if self.device:isMTK() then
             self.mech_refresh = refresh_mtk
 
+            self.waveform_a2 = C.MTK_WAVEFORM_MODE_A2
             self.waveform_fast = C.MTK_WAVEFORM_MODE_DU
             self.waveform_ui = C.WAVEFORM_MODE_AUTO
             self.waveform_flashui = self.waveform_ui
@@ -820,6 +826,7 @@ function framebuffer:init()
         self.mech_refresh = refresh_kobo
         self.mech_wait_update_complete = kobo_mxc_wait_for_update_complete
 
+        self.waveform_a2 = C.WAVEFORM_MODE_A2
         self.waveform_fast = C.WAVEFORM_MODE_DU
         self.waveform_ui = C.WAVEFORM_MODE_AUTO
         self.waveform_flashui = self.waveform_ui
@@ -892,6 +899,7 @@ function framebuffer:init()
         self.mech_refresh = refresh_pocketbook
         self.mech_wait_update_complete = pocketbook_mxc_wait_for_update_complete
 
+        self.waveform_a2 = C.WAVEFORM_MODE_A2
         self.wf_level_max = 3
         local level = self:getWaveformLevel()
         -- Level 0 is most conservative.
@@ -933,6 +941,7 @@ function framebuffer:init()
         self.mech_refresh = refresh_remarkable
         self.mech_wait_update_complete = remarkable_mxc_wait_for_update_complete
 
+        self.waveform_a2 = C.WAVEFORM_MODE_A2
         self.waveform_fast = C.WAVEFORM_MODE_DU
         self.waveform_ui = C.WAVEFORM_MODE_GL16
         self.waveform_flashui = C.WAVEFORM_MODE_GC16
@@ -955,6 +964,7 @@ function framebuffer:init()
         self.mech_refresh = refresh_sony_prstux
         self.mech_wait_update_complete = sony_prstux_mxc_wait_for_update_complete
 
+        self.waveform_a2 = C.WAVEFORM_MODE_A2
         self.waveform_fast = C.WAVEFORM_MODE_DU
         self.waveform_ui = C.WAVEFORM_MODE_AUTO
         self.waveform_flashui = self.waveform_ui
@@ -974,6 +984,7 @@ function framebuffer:init()
         self.mech_refresh = refresh_cervantes
         self.mech_wait_update_complete = cervantes_mxc_wait_for_update_complete
 
+        self.waveform_a2 = C.WAVEFORM_MODE_A2
         self.waveform_fast = C.WAVEFORM_MODE_DU
         self.waveform_ui = C.WAVEFORM_MODE_AUTO
         self.waveform_flashui = self.waveform_ui