Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932333AbbFYKUG (ORCPT ); Thu, 25 Jun 2015 06:20:06 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:39649 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752574AbbFYKDL (ORCPT ); Thu, 25 Jun 2015 06:03:11 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jim Bride , Jani Nikula , Luis Henriques Subject: [PATCH 3.16.y-ckt 17/71] drm/i915/hsw: Fix workaround for server AUX channel clock divisor Date: Thu, 25 Jun 2015 11:01:56 +0100 Message-Id: <1435226570-3669-18-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1435226570-3669-1-git-send-email-luis.henriques@canonical.com> References: <1435226570-3669-1-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 Content-Length: 1821 Lines: 53 3.16.7-ckt14 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jim Bride commit e058c945e03a629c99606452a6931f632dd28903 upstream. According to the HSW b-spec we need to try clock divisors of 63 and 72, each 3 or more times, when attempting DP AUX channel communication on a server chipset. This actually wasn't happening due to a short-circuit that only checked the DP_AUX_CH_CTL_DONE bit in status rather than checking that the operation was done and that DP_AUX_CH_CTL_TIME_OUT_ERROR was not set. [v2] Implemented alternate solution suggested by Jani Nikula. Signed-off-by: Jim Bride Signed-off-by: Jani Nikula Signed-off-by: Luis Henriques --- drivers/gpu/drm/i915/intel_dp.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index d2f1431eb428..b5660eb078f6 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -597,10 +597,8 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, DP_AUX_CH_CTL_RECEIVE_ERROR)) continue; if (status & DP_AUX_CH_CTL_DONE) - break; + goto done; } - if (status & DP_AUX_CH_CTL_DONE) - break; } if ((status & DP_AUX_CH_CTL_DONE) == 0) { @@ -609,6 +607,7 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, goto out; } +done: /* Check for timeout or receive error. * Timeouts occur when the sink is not connected */ -- 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/