@@ -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
This is a note to let you know that I have just added a patch titled drm/i915/dp: add native aux defer retry limit to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.20. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From e4ae2b495041a5229604a338a450f331cfb4f365 Mon Sep 17 00:00:00 2001 From: Jani Nikula <jani.nikula@intel.com> Date: Tue, 11 Feb 2014 11:52:05 +0200 Subject: drm/i915/dp: add native aux defer retry limit commit f51a44b9a6c4982cc25bfb3727de9bb893621ebc upstream. Retrying indefinitely places too much trust on the aux implementation of the sink devices. Reported-by: Daniel Martin <consume.noise@gmail.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71267 Signed-off-by: Jani Nikula <jani.nikula@intel.com> Tested-by: Theodore Ts'o <tytso@mit.edu> Tested-by: Sree Harsha Totakura <freedesktop@h.totakura.in> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/gpu/drm/i915/intel_dp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) -- 1.8.3.2