Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755658AbbDKWqA (ORCPT ); Sat, 11 Apr 2015 18:46:00 -0400 Received: from iodev.co.uk ([82.211.30.53]:54169 "EHLO iodev.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752789AbbDKWp5 (ORCPT ); Sat, 11 Apr 2015 18:45:57 -0400 X-Greylist: delayed 304 seconds by postgrey-1.27 at vger.kernel.org; Sat, 11 Apr 2015 18:45:57 EDT From: Ismael Luceno To: linux-kernel@vger.kernel.org Cc: Ismael Luceno Subject: [PATCH] drm/i915: Fix screen flickering on X Date: Sat, 11 Apr 2015 19:40:34 -0300 Message-Id: <1428792034-6131-1-git-send-email-ismael@iodev.co.uk> X-Mailer: git-send-email 2.3.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2328 Lines: 62 A bisect showed that commit 32b7eeec4d1e861230b09d437e95d76c86ff4a68 introduced the issue. The issue starts as soon as X takes control of the screen, even if just a plain X doing nothing, so based on the code touched by the commit I thought it had to be related to the so called "hardware cursor". I confirmed it when hiding the cursor made the flickering go away. The aforementioned commit removed some suspicious code, and the Programmer's Reference Manual confirmed my suspicion: "Incorrectly programmed watermark values can result in screen corruption. The watermarks should be calculated and programmed when any of the watermark calculation inputs change. This includes planes enabling or disabling, plane source format or size changing, etc." So I'm re-adding the few lines that update the watermarks after a cursor size change. Signed-off-by: Ismael Luceno --- drivers/gpu/drm/i915/intel_display.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index f75173c..e23f062 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -12258,6 +12258,7 @@ intel_commit_cursor_plane(struct drm_plane *plane, struct intel_crtc *intel_crtc; struct intel_plane *intel_plane = to_intel_plane(plane); struct drm_i915_gem_object *obj = intel_fb_obj(state->base.fb); + unsigned old_width; uint32_t addr; crtc = crtc ? crtc : plane->crtc; @@ -12282,11 +12283,15 @@ intel_commit_cursor_plane(struct drm_plane *plane, intel_crtc->cursor_addr = addr; intel_crtc->cursor_bo = obj; update: + old_width = intel_crtc->cursor_width; intel_crtc->cursor_width = state->base.crtc_w; intel_crtc->cursor_height = state->base.crtc_h; - if (intel_crtc->active) + if (intel_crtc->active) { + if (old_width != intel_crtc->cursor_width) + intel_update_watermarks(crtc); intel_crtc_update_cursor(crtc, state->visible); + } } static struct drm_plane *intel_cursor_plane_create(struct drm_device *dev, -- 2.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/