From 59fb8218c8e5001f854e7d5fdb5fb135cba58102 Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Tue, 9 Feb 2021 04:19:16 +0200 Subject: drm/i915: Disallow plane x+w>stride on ilk+ with X-tiling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ilk+ planes get notably unhappy when the plane x+w exceeds the stride. This wasn't a problem previously because we always aligned SURF to the closest tile boundary so the x offset never got particularly large. But now with async flips we have to align to 256KiB instead and thus this becomes a real issue. On ilk/snb/ivb it looks like the accesses just wrap early to the next tile row when scanout goes past the SURF+n*stride boundary, hsw/bdw suffer more heavily and start to underrun constantly. i965/g4x appear to be immune. vlv/chv I've not yet checked. Let's borrow another trick from the skl+ code and search backwards for a better SURF offset in the hopes of getting the x offset below the limit. IIRC when I ran into a similar issue on skl years ago it was causing the hardware to fall over pretty hard as well. And let's be consistent and include i965/g4x in the check as well, just in case I just got super lucky somehow when I wasn't able to reproduce the issue. Not that it really matters since we still use 4k SURF alignment for i965/g4x anyway. Fixes: 6ede6b0616b2 ("drm/i915: Implement async flips for vlv/chv") Fixes: 4bb18054adc4 ("drm/i915: Implement async flip for ilk/snb") Fixes: 2a636e240c77 ("drm/i915: Implement async flip for ivb/hsw") Fixes: cda195f13abd ("drm/i915: Implement async flips for bdw") Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20210209021918.16234-1-ville.syrjala@linux.intel.com Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/display/i9xx_plane.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/gpu/drm/i915/display/i9xx_plane.c b/drivers/gpu/drm/i915/display/i9xx_plane.c index 0523e2c79d16..8a52beaed2da 100644 --- a/drivers/gpu/drm/i915/display/i9xx_plane.c +++ b/drivers/gpu/drm/i915/display/i9xx_plane.c @@ -255,6 +255,33 @@ int i9xx_check_plane_surface(struct intel_plane_state *plane_state) else offset = 0; + /* + * When using an X-tiled surface the plane starts to + * misbehave if the x offset + width exceeds the stride. + * hsw/bdw: underrun galore + * ilk/snb/ivb: wrap to the next tile row mid scanout + * i965/g4x: so far appear immune to this + * vlv/chv: TODO check + * + * Linear surfaces seem to work just fine, even on hsw/bdw + * despite them not using the linear offset anymore. + */ + if (INTEL_GEN(dev_priv) >= 4 && fb->modifier == I915_FORMAT_MOD_X_TILED) { + u32 alignment = intel_surf_alignment(fb, 0); + int cpp = fb->format->cpp[0]; + + while ((src_x + src_w) * cpp > plane_state->color_plane[0].stride) { + if (offset == 0) { + drm_dbg_kms(&dev_priv->drm, + "Unable to find suitable display surface offset due to X-tiling\n"); + return -EINVAL; + } + + offset = intel_plane_adjust_aligned_offset(&src_x, &src_y, plane_state, 0, + offset, offset - alignment); + } + } + /* * Put the final coordinates back so that the src * coordinate checks will see the right values. -- cgit v1.2.3