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| author | Alex Deucher <alexander.deucher@amd.com> | 2011-10-03 09:13:46 -0400 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2011-10-03 18:37:31 +0100 |
| commit | 6375bda073724ead7df08746866b724b1799a295 (patch) | |
| tree | e2fb38f42845db6a31a532611e1f4e4dd164bc12 | |
| parent | 109bc10d30f33e84f1d7289f0039e0c858ade82f (diff) | |
| download | linux-2.6-6375bda073724ead7df08746866b724b1799a295.tar.gz linux-2.6-6375bda073724ead7df08746866b724b1799a295.tar.xz | |
drm/radeon/kms: add retry limits for native DP aux defer
The previous code could potentially loop forever. Limit
the number of DP aux defer retries to 4 for native aux
transactions, same as i2c over aux transactions.
Noticed by: Brad Campbell <lists2009@fnarfbargle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Brad Campbell <lists2009@fnarfbargle.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
| -rw-r--r-- | drivers/gpu/drm/radeon/atombios_dp.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index f526fa77e32..4da23889fea 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -115,6 +115,7 @@ static int radeon_dp_aux_native_write(struct radeon_connector *radeon_connector, u8 msg[20]; int msg_bytes = send_bytes + 4; u8 ack; + unsigned retry; if (send_bytes > 16) return -1; @@ -125,20 +126,20 @@ static int radeon_dp_aux_native_write(struct radeon_connector *radeon_connector, msg[3] = (msg_bytes << 4) | (send_bytes - 1); memcpy(&msg[4], send, send_bytes); - while (1) { + for (retry = 0; retry < 4; retry++) { ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus, msg, msg_bytes, NULL, 0, delay, &ack); 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) udelay(400); else return -EIO; } - return send_bytes; + return -EIO; } static int radeon_dp_aux_native_read(struct radeon_connector *radeon_connector, @@ -149,13 +150,14 @@ static int radeon_dp_aux_native_read(struct radeon_connector *radeon_connector, int msg_bytes = 4; u8 ack; int ret; + unsigned retry; msg[0] = address; msg[1] = address >> 8; msg[2] = AUX_NATIVE_READ << 4; msg[3] = (msg_bytes << 4) | (recv_bytes - 1); - while (1) { + for (retry = 0; retry < 4; retry++) { ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus, msg, msg_bytes, recv, recv_bytes, delay, &ack); if (ret < 0) @@ -169,6 +171,8 @@ static int radeon_dp_aux_native_read(struct radeon_connector *radeon_connector, else return -EIO; } + + return -EIO; } static void radeon_write_dpcd_reg(struct radeon_connector *radeon_connector, |