The patch below does not apply to the 5.7-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 92e0575b99835b5b3aaab2132dd551e0e04eb96a Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= ville.syrjala@linux.intel.com Date: Sat, 11 Jul 2020 11:03:36 +0300 Subject: [PATCH] drm/i915: Recalculate FBC w/a stride when needed MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

Currently we're failing to recalculate the gen9 FBC w/a stride unless something more drastic than just the modifier itself has changed. This often leaves us with FBC enabled with the linear fbdev framebuffer without the w/a stride enabled. That will cause an immediate underrun and FBC will get promptly disabled.

Fix the problem by checking if the w/a stride is about to change, and go through the full dance if so. This part of the FBC code is still pretty much a disaster and will need lots more work. But this should at least fix the immediate issue.

v2: Deactivate FBC when the modifier changes since that will likely require resetting the w/a CFB stride

Cc: stable@vger.kernel.org Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20200711080336.13423-1-ville.s... Reviewed-by: José Roberto de Souza jose.souza@intel.com (cherry picked from commit 0428ab013fdd39dbfb8f4cd8ad2b60af3776c6b9) Signed-off-by: Jani Nikula jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c index a65d9d8b79a7..412572f88b67 100644 --- a/drivers/gpu/drm/i915/display/intel_fbc.c +++ b/drivers/gpu/drm/i915/display/intel_fbc.c @@ -719,6 +719,25 @@ static bool intel_fbc_cfb_size_changed(struct drm_i915_private *dev_priv) fbc->compressed_fb.size * fbc->threshold; }

+static u16 intel_fbc_gen9_wa_cfb_stride(struct drm_i915_private *dev_priv) +{ + struct intel_fbc *fbc = &dev_priv->fbc; + struct intel_fbc_state_cache *cache = &fbc->state_cache; + + if ((IS_GEN9_BC(dev_priv) || IS_BROXTON(dev_priv)) && + cache->fb.modifier != I915_FORMAT_MOD_X_TILED) + return DIV_ROUND_UP(cache->plane.src_w, 32 * fbc->threshold) * 8; + else + return 0; +} + +static bool intel_fbc_gen9_wa_cfb_stride_changed(struct drm_i915_private *dev_priv) +{ + struct intel_fbc *fbc = &dev_priv->fbc; + + return fbc->params.gen9_wa_cfb_stride != intel_fbc_gen9_wa_cfb_stride(dev_priv); +} + static bool intel_fbc_can_enable(struct drm_i915_private *dev_priv) { struct intel_fbc *fbc = &dev_priv->fbc; @@ -877,6 +896,7 @@ static void intel_fbc_get_reg_params(struct intel_crtc *crtc, params->crtc.i9xx_plane = to_intel_plane(crtc->base.primary)->i9xx_plane;

params->fb.format = cache->fb.format; + params->fb.modifier = cache->fb.modifier; params->fb.stride = cache->fb.stride;

params->cfb_size = intel_fbc_calculate_cfb_size(dev_priv, cache); @@ -906,6 +926,9 @@ static bool intel_fbc_can_flip_nuke(const struct intel_crtc_state *crtc_state) if (params->fb.format != cache->fb.format) return false;

+ if (params->fb.modifier != cache->fb.modifier) + return false; + if (params->fb.stride != cache->fb.stride) return false;

@@ -1185,7 +1208,8 @@ void intel_fbc_enable(struct intel_atomic_state *state,

if (fbc->crtc) { if (fbc->crtc != crtc || - !intel_fbc_cfb_size_changed(dev_priv)) + (!intel_fbc_cfb_size_changed(dev_priv) && + !intel_fbc_gen9_wa_cfb_stride_changed(dev_priv))) goto out;

__intel_fbc_disable(dev_priv); @@ -1207,12 +1231,7 @@ void intel_fbc_enable(struct intel_atomic_state *state, goto out; }

- if ((IS_GEN9_BC(dev_priv) || IS_BROXTON(dev_priv)) && - plane_state->hw.fb->modifier != I915_FORMAT_MOD_X_TILED) - cache->gen9_wa_cfb_stride = - DIV_ROUND_UP(cache->plane.src_w, 32 * fbc->threshold) * 8; - else - cache->gen9_wa_cfb_stride = 0; + cache->gen9_wa_cfb_stride = intel_fbc_gen9_wa_cfb_stride(dev_priv);

drm_dbg_kms(&dev_priv->drm, "Enabling FBC on pipe %c\n", pipe_name(crtc->pipe)); diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index f79f118bf192..ae99a9190200 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -440,6 +440,7 @@ struct intel_fbc { struct { const struct drm_format_info *format; unsigned int stride; + u64 modifier; } fb;

int cfb_size;