Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753662AbaLOOhg (ORCPT ); Mon, 15 Dec 2014 09:37:36 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:38897 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751339AbaLOO3B (ORCPT ); Mon, 15 Dec 2014 09:29:01 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Daniel Vetter , Jani Nikula , Luis Henriques Subject: [PATCH 3.16.y-ckt 136/168] drm/i915: More cautious with pch fifo underruns Date: Mon, 15 Dec 2014 14:26:30 +0000 Message-Id: <1418653622-21105-137-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1418653622-21105-1-git-send-email-luis.henriques@canonical.com> References: <1418653622-21105-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Vetter commit b68362278af94e1171f5be9d4e44988601fb0439 upstream. Apparently PCH fifo underruns are tricky, we have plenty reports that we see the occasional underrun (especially at boot-up). So for a change let's see what happens when we don't re-enable pch fifo underrun reporting when the pipe is disabled. This means that the kernel can't catch pch fifo underruns when they happen (except when all pipes are on on the pch). But we'll still catch underruns when disabling the pipe again. So not a terrible reduction in test coverage. Since the DRM_ERROR is new and hence a regression plan B would be to revert it back to a debug output. Which would be a lot worse than this hack for underrun test coverage in the wild. See the referenced discussions for more. References: http://mid.gmane.org/CA+gsUGRfGe3t4NcjdeA=qXysrhLY3r4CEu7z4bjTwxi1uOfy+g@mail.gmail.com Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85898 References: https://bugs.freedesktop.org/show_bug.cgi?id=85898 References: https://bugs.freedesktop.org/show_bug.cgi?id=86233 References: https://bugs.freedesktop.org/show_bug.cgi?id=86478 Signed-off-by: Daniel Vetter Tested-by: lu hua Reviewed-by: Paulo Zanoni Signed-off-by: Jani Nikula Signed-off-by: Luis Henriques --- drivers/gpu/drm/i915/intel_display.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 6b835b86fbfd..abed8ee8e2d7 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4183,7 +4183,6 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc) ironlake_fdi_disable(crtc); ironlake_disable_pch_transcoder(dev_priv, pipe); - intel_set_pch_fifo_underrun_reporting(dev, pipe, true); if (HAS_PCH_CPT(dev)) { /* disable TRANS_DP_CTL */ @@ -4250,7 +4249,6 @@ static void haswell_crtc_disable(struct drm_crtc *crtc) if (intel_crtc->config.has_pch_encoder) { lpt_disable_pch_transcoder(dev_priv); - intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_A, true); intel_ddi_fdi_disable(crtc); } -- 2.1.3 -- 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/