From 77bf89468ae855a55a837c0289acb92e11f42846 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Wed, 6 Mar 2024 06:08:05 +0200 Subject: [PATCH] drm/i915/dsb: Fix DSB vblank waits when using VRR MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit f12751168f1a49ebb84b8056cf038973c53b284f upstream. Looks like the undelayed vblank gets signalled exactly when the active period ends. That is a problem for DSB+VRR when we are already in vblank and expect DSB to start executing as soon as we send the push. Instead of starting, the DSB just keeps on waiting for the undelayed vblank which won't signal until the end of the next frame's active period, which is far too late. The end result is that DSB won't have even started executing by the time the flips/etc. have completed. We then wait for an extra 1ms, after which we terminate the DSB and report a timeout: [drm] *ERROR* [CRTC:80:pipe A] DSB 0 timed out waiting for idle (current head=0xfedf4000, head=0x0, tail=0x1080) To fix this let's configure DSB to use the so called VRR "safe window" instead of the undelayed vblank to trigger the DSB vblank logic, when VRR is enabled. Cc: stable@vger.kernel.org Fixes: 34d8311f4a1c ("drm/i915/dsb: Re-instate DSB for LUT updates") Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9927 Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20240306040806.21697-3-ville.syrjala@linux.intel.com Reviewed-by: Animesh Manna (cherry picked from commit 41429d9b68367596eb3d6d5961e6295c284622a7) Signed-off-by: Rodrigo Vivi Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/display/intel_dsb.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c index 7fd6280c54a79..15c3dd5d388b2 100644 --- a/drivers/gpu/drm/i915/display/intel_dsb.c +++ b/drivers/gpu/drm/i915/display/intel_dsb.c @@ -339,6 +339,17 @@ static int intel_dsb_dewake_scanline(const struct intel_crtc_state *crtc_state) return max(0, vblank_start - intel_usecs_to_scanlines(adjusted_mode, latency)); } +static u32 dsb_chicken(struct intel_crtc *crtc) +{ + if (crtc->mode_flags & I915_MODE_FLAG_VRR) + return DSB_CTRL_WAIT_SAFE_WINDOW | + DSB_CTRL_NO_WAIT_VBLANK | + DSB_INST_WAIT_SAFE_WINDOW | + DSB_INST_NO_WAIT_VBLANK; + else + return 0; +} + static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl, int dewake_scanline) { @@ -360,6 +371,9 @@ static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl, intel_de_write_fw(dev_priv, DSB_CTRL(pipe, dsb->id), ctrl | DSB_ENABLE); + intel_de_write_fw(dev_priv, DSB_CHICKEN(pipe, dsb->id), + dsb_chicken(crtc)); + intel_de_write_fw(dev_priv, DSB_HEAD(pipe, dsb->id), i915_ggtt_offset(dsb->vma));