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authorJani Nikula <jani.nikula@intel.com>2014-02-11 11:52:05 +0200
committerJiri Slaby <jslaby@suse.cz>2014-03-05 17:13:57 +0100
commit04ea7f8d985ba915d9eebec9ae724e996d1a5404 (patch)
tree115d6ba07af77f819899dd642817835f8d98d565
parent4a036dd40a68428a35f3272a3275b3f35099dd43 (diff)
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: Jiri Slaby <jslaby@suse.cz>
-rw-r--r--drivers/gpu/drm/i915/intel_dp.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e5c79ae1614b..b0191f25cd55 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -450,6 +450,7 @@ 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)
@@ -460,18 +461,20 @@ 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 */
@@ -493,6 +496,7 @@ 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;
@@ -503,7 +507,7 @@ 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)
@@ -520,6 +524,9 @@ 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