Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935175AbcJTPFu (ORCPT ); Thu, 20 Oct 2016 11:05:50 -0400 Received: from mx2.suse.de ([195.135.220.15]:44502 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934150AbcJTPFe (ORCPT ); Thu, 20 Oct 2016 11:05:34 -0400 From: Takashi Iwai To: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, Daniel Vetter , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= , David Airlie Subject: [PATCH v2] drm/fb-helper: Don't call dirty callback for untouched clips Date: Thu, 20 Oct 2016 17:05:30 +0200 Message-Id: <20161020150530.5787-1-tiwai@suse.de> X-Mailer: git-send-email 2.10.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1925 Lines: 48 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') Cc: Signed-off-by: Takashi Iwai --- v1->v2: simplified the code as suggested by Ville drivers/gpu/drm/drm_fb_helper.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 03414bde1f15..aae7df01864d 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -644,7 +644,9 @@ 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); } /** -- 2.10.1