Patch "drm/fb-helper: Don't call dirty callback for untouched clips" has been added to the 4.8-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/fb-helper: Don't call dirty callback for untouched clips

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-fb-helper-don-t-call-dirty-callback-for-untouched-clips.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 87d3b6588f9bf205902868d3e5baf68e37ad4ae1 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 20 Oct 2016 17:05:30 +0200
Subject: drm/fb-helper: Don't call dirty callback for untouched clips
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Takashi Iwai <tiwai@suse.de>

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 <tiwai@suse.de>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161020150530.5787-1-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/drm_fb_helper.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- 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(str
 	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);
 }
 
 /**


Patches currently in stable-queue which might be from tiwai@suse.de are

queue-4.8/alsa-hda-adding-a-new-group-of-pin-cfg-into-alc295-pin-quirk-table.patch
queue-4.8/drm-fb-helper-don-t-call-dirty-callback-for-untouched-clips.patch
queue-4.8/alsa-seq-fix-time-account-regression.patch
queue-4.8/alsa-hda-fix-headset-mic-detection-problem-for-two-dell-laptops.patch
queue-4.8/alsa-hda-allow-40-bit-dma-mask-for-nvidia-devices.patch
queue-4.8/alsa-hda-fix-surround-output-pins-for-asrock-b150m-mobo.patch
queue-4.8/alsa-usb-audio-add-quirk-for-syntek-stk1160.patch