Created attachment 112399 [details] dmesg ==System Environment== -------------------------- Regression: Yes. Non-working platforms: I've faced on BDW and BSW but I believe it can affect all platforms. ==kernel== drm-intel-nightly: 2015y-01m-17d-09h-41m-12s UTC integration manifest ==Bug detailed description== System gets impossible to use due very slow cursor movements. bisect took me to the point we change to atomic plane helpers, but it can be a miss usage of atomic helpers everywhere else. drm/i915: Move to atomic plane helpers (v9) attached dmesg shows many calls of drm_atomic_set_fb_for_plane whenever moving cursor. [ 103.143044] [drm:drm_atomic_set_fb_for_plane] Set [FB:45] for plane state ffff88009a1ce680 [ 103.159720] [drm:drm_atomic_set_fb_for_plane] Set [FB:45] for plane state ffff88009a1ce300 [ 103.176653] [drm:drm_atomic_set_fb_for_plane] Set [FB:45] for plane state ffff88009a1ce680 [ 104.696065] [drm:drm_atomic_set_fb_for_plane] Set [NOFB] for plane state ffff88009b0a2600 ==Reproduce steps== Just boot a system with kde environment and *try* to use the cursor.
See discussion in thread http://mid.gmane.org/20150117100635.GA1281@hudson.localdomain
I believe this patch: http://lists.freedesktop.org/archives/dri-devel/2015-January/075670.html will solve the immediate problem being reported here, at least for the existing Intel userspace I'm aware of. The problem here is that the display server wants to update the cursor faster than the display refresh rate and we were throttling the updates to vblank. The patch here removes that throttling for the case where the cursor is only being moved to a new position, but doesn't address the case where the cursor image changes. If there are any userspace display servers that also try to update the cursor image to a new framebuffer while reprogramming the cursor faster than the refresh rate, they'll still see the throttling. I'm not sure if there are any existing userspace display servers that work that way today.
Thanks for the fix. I hope that lands fast so we can close this bug. Tested-by: Rodrigo Vivi <rodrigo.vivi@intel.com>r
Thanks for the fix
*** Bug 88676 has been marked as a duplicate of this bug. ***
Closing old verified+fixed.
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