From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755788AbaCYRss (ORCPT ); Tue, 25 Mar 2014 13:48:48 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:55787 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754813AbaCYRVC (ORCPT ); Tue, 25 Mar 2014 13:21:02 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jani Nikula , Daniel Vetter , Kamal Mostafa Subject: [PATCH 3.8 19/81] drm/i915/dp: add native aux defer retry limit Date: Tue, 25 Mar 2014 10:15:32 -0700 Message-Id: <1395767794-5012-20-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1395767794-5012-1-git-send-email-kamal@canonical.com> References: <1395767794-5012-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8.13.20 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jani Nikula commit f51a44b9a6c4982cc25bfb3727de9bb893621ebc upstream. Retrying indefinitely places too much trust on the aux implementation of the sink devices. Reported-by: Daniel Martin Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71267 Signed-off-by: Jani Nikula Tested-by: Theodore Ts'o Tested-by: Sree Harsha Totakura Signed-off-by: Daniel Vetter Signed-off-by: Kamal Mostafa --- drivers/gpu/drm/i915/intel_dp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 394fa61..64c9d7e 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -491,6 +491,7 @@ intel_dp_aux_native_write(struct intel_dp *intel_dp, uint8_t msg[20]; int msg_bytes; uint8_t ack; + int retry; intel_dp_check_edp(intel_dp); if (send_bytes > 16) @@ -501,18 +502,20 @@ intel_dp_aux_native_write(struct intel_dp *intel_dp, msg[3] = send_bytes - 1; memcpy(&msg[4], send, send_bytes); msg_bytes = send_bytes + 4; - for (;;) { + for (retry = 0; retry < 7; retry++) { ret = intel_dp_aux_ch(intel_dp, msg, msg_bytes, &ack, 1); if (ret < 0) return ret; if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) - break; + return send_bytes; else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER) usleep_range(400, 500); else return -EIO; } - return send_bytes; + + DRM_ERROR("too many retries, giving up\n"); + return -EIO; } /* Write a single byte to the aux channel in native mode */ @@ -534,6 +537,7 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp, int reply_bytes; uint8_t ack; int ret; + int retry; intel_dp_check_edp(intel_dp); msg[0] = AUX_NATIVE_READ << 4; @@ -544,7 +548,7 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp, msg_bytes = 4; reply_bytes = recv_bytes + 1; - for (;;) { + for (retry = 0; retry < 7; retry++) { ret = intel_dp_aux_ch(intel_dp, msg, msg_bytes, reply, reply_bytes); if (ret == 0) @@ -561,6 +565,9 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp, else return -EIO; } + + DRM_ERROR("too many retries, giving up\n"); + return -EIO; } static int -- 1.8.3.2