commit f51a44b9a6c4982cc25bfb3727de9bb893621ebc upstream. Retrying indefinitely places too much trust on the aux implementation of the sink devices. Reported-by: Daniel Martin <consume.noise@xxxxxxxxx> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71267 Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Tested-by: Theodore Ts'o <tytso@xxxxxxx> Tested-by: Sree Harsha Totakura <freedesktop@xxxxxxxxxxxxx> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx> --- 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 24cede7bcb62..3e1b348de244 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -537,6 +537,7 @@ intel_dp_aux_native_write(struct intel_dp *intel_dp, uint8_t msg[20]; int msg_bytes; uint8_t ack; + int retry; if (WARN_ON(send_bytes > 16)) return -E2BIG; @@ -548,18 +549,20 @@ 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 */ @@ -581,6 +584,7 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp, int reply_bytes; uint8_t ack; int ret; + int retry; if (WARN_ON(recv_bytes > 19)) return -E2BIG; @@ -594,7 +598,7 @@ 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) @@ -611,6 +615,9 @@ 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 -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html