From 4a477651033e48851386d12e773584c99a878670 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 17 Aug 2018 09:24:05 +0100 Subject: [PATCH] drm/i915: Keep physical cursors pinned while in use MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The optimisation inherent in commit 6a2c4232ece1 ("drm/i915: Make the physical object coherent with GTT") relies on that once we allocated a cursor we would have coherent, zero overhead access to the scanout plane holding the cursor. That is we could then do the very frequent cursor updates X enjoys with no indirection or kernel involvement. However, that all hinges on the GGTT mmap of the cursor being pinned and not require refaulting on each access -- handling such a page fault likely requires the busy GGTT to be rearranged causing a stall. A very simple fix is then to handle the physical cursor exactly like other cursors and keep its vma pinned while active. References: https://bugs.freedesktop.org/show_bug.cgi?id=107600 References: 6a2c4232ece1 ("drm/i915: Make the physical object coherent with GTT") Signed-off-by: Chris Wilson Cc: Ville Syrjälä Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20180817082405.755-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_display.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index ec3e24f..b79ad9c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -12969,8 +12969,11 @@ static int intel_plane_pin_fb(struct intel_plane_state *plane_state) INTEL_INFO(dev_priv)->cursor_needs_physical) { struct drm_i915_gem_object *obj = intel_fb_obj(fb); const int align = intel_cursor_alignment(dev_priv); + int err; - return i915_gem_object_attach_phys(obj, align); + err = i915_gem_object_attach_phys(obj, align); + if (err) + return err; } vma = intel_pin_and_fence_fb_obj(fb, -- 2.7.4