On 23/09/16 10:06 PM, Takashi Iwai wrote: > radeon_cursor_move_unlock() contains a workaround for AVIVO chips that > are older than DCE6 when the cursor ends on 128 pixel boundary. It > decreases the position when the calculated end position is on 128 > pixel boundary. However, it hits also the condition where x=-1 and > width=1 are passed, since cursor_end is 0 (which is aligned with 128, > too). Then the value gets decreased and it hits WARN_ON_ONCE() > below, eventually screws up the GPU. > > The fix is simply to skip the workaround when x is already zero. > Also, remove the superfluous WARN_ON_ON() for the negative value check > that wouldn't happen any longer after this change. > > Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1000433 > Cc: <stable at vger.kernel.org> > Signed-off-by: Takashi Iwai <tiwai at suse.de> > --- > drivers/gpu/drm/radeon/radeon_cursor.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/radeon/radeon_cursor.c > b/drivers/gpu/drm/radeon/radeon_cursor.c > index 2a10e24b34b1..4e436eb49a56 100644 > --- a/drivers/gpu/drm/radeon/radeon_cursor.c > +++ b/drivers/gpu/drm/radeon/radeon_cursor.c > @@ -193,10 +193,8 @@ static int radeon_cursor_move_locked(struct drm_crtc > *crtc, int x, int y) > if (w <= 0) { > w = 1; > cursor_end = x - xorigin + w; > - if (!(cursor_end & 0x7f)) { > + if (x > 0 && !(cursor_end & 0x7f)) > x--; > - WARN_ON_ONCE(x < 0); > - } > }
The problem with this change is that the horizontal cursor end position can again and up as a multiple of 128, which this code is trying to avoid, because it can break the cursor with some versions of AVIVO / DCE display engines. Attached is a proof-of-concept (only compile tested) alternative fix which hides the cursor while it's out of bounds. I'll test it, clean it up and split it up into multiple patches when I get a chance, but maybe you or the reporter of the referenced bug can test it in the meantime. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer -------------- next part -------------- A non-text attachment was scrubbed... Name: radeon-cursor-out-of-bounds.diff Type: text/x-patch Size: 4154 bytes Desc: not available URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20160926/20463735/attachment-0001.bin>
