The patch below does not apply to the 3.13-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f51a44b9a6c4982cc25bfb3727de9bb893621ebc Mon Sep 17 00:00:00 2001 From: Jani Nikula <[email protected]> Date: Tue, 11 Feb 2014 11:52:05 +0200 Subject: [PATCH] drm/i915/dp: add native aux defer retry limit Retrying indefinitely places too much trust on the aux implementation of the sink devices. Reported-by: Daniel Martin <[email protected]> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71267 Signed-off-by: Jani Nikula <[email protected]> Cc: [email protected] Tested-by: Theodore Ts'o <[email protected]> Tested-by: Sree Harsha Totakura <[email protected]> Signed-off-by: Daniel Vetter <[email protected]> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index c36960488c89..57552eb386b0 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; @@ -548,19 +549,21 @@ 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; ack >>= 4; if ((ack & DP_AUX_NATIVE_REPLY_MASK) == DP_AUX_NATIVE_REPLY_ACK) - break; + return send_bytes; else if ((ack & DP_AUX_NATIVE_REPLY_MASK) == DP_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 */ @@ -582,6 +585,7 @@ 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; @@ -595,7 +599,7 @@ 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) @@ -612,6 +616,9 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
