Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932472AbbFSUsu (ORCPT ); Fri, 19 Jun 2015 16:48:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51440 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756288AbbFSUjq (ORCPT ); Fri, 19 Jun 2015 16:39:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jim Bride , Jani Nikula Subject: [PATCH 4.0 076/105] drm/i915/hsw: Fix workaround for server AUX channel clock divisor Date: Fri, 19 Jun 2015 13:36:06 -0700 Message-Id: <20150619203600.422383901@linuxfoundation.org> X-Mailer: git-send-email 2.4.4 In-Reply-To: <20150619203558.187802739@linuxfoundation.org> References: <20150619203558.187802739@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1578 Lines: 52 4.0-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: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_dp.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -881,10 +881,8 @@ intel_dp_aux_ch(struct intel_dp *intel_d 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) { @@ -893,6 +891,7 @@ intel_dp_aux_ch(struct intel_dp *intel_d 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 Please read the FAQ at http://www.tux.org/lkml/