From: Takashi Iwai Date: Thu, 20 Oct 2016 15:05:30 +0000 (+0200) Subject: drm/fb-helper: Don't call dirty callback for untouched clips X-Git-Tag: v4.8.7~29 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6222f1e0b9ef0d0c89183cadcc1e780661ce08d3;p=thirdparty%2Fkernel%2Fstable.git drm/fb-helper: Don't call dirty callback for untouched clips commit 87d3b6588f9bf205902868d3e5baf68e37ad4ae1 upstream. Since 4.7 kernel, we've seen the error messages like kernel: [TTM] Buffer eviction failed kernel: qxl 0000:00:02.0: object_init failed for (4026540032, 0x00000001) kernel: [drm:qxl_alloc_bo_reserved [qxl]] *ERROR* failed to allocate VRAM BO on QXL when switching and accessing on VT. The culprit was the generic deferred_io code (qxl driver switched to it since 4.7). There is a race between the dirty clip update and the call of callback. In drm_fb_helper_dirty(), the dirty clip is updated in the spinlock, while it kicks off the update worker outside the spinlock. Meanwhile the update worker clears the dirty clip in the spinlock, too. Thus, when drm_fb_helper_dirty() is called concurrently, schedule_work() is called after the clip is cleared in the first worker call. This patch addresses it by validating the clip before calling the dirty fb callback. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98322 Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1003298 Fixes: eaa434defaca ('drm/fb-helper: Add fb_deferred_io support') Signed-off-by: Takashi Iwai Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20161020150530.5787-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 0a06f9120b5a6..91b46ffa92c2e 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -632,7 +632,9 @@ static void drm_fb_helper_dirty_work(struct work_struct *work) clip->x2 = clip->y2 = 0; spin_unlock_irqrestore(&helper->dirty_lock, flags); - helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip_copy, 1); + /* call dirty callback only when it has been really touched */ + if (clip_copy.x1 < clip_copy.x2 && clip_copy.y1 < clip_copy.y2) + helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip_copy, 1); } /**