From 109bc10d30f33e84f1d7289f0039e0c858ade82f Mon Sep 17 00:00:00 2001 From: Alex Deucher Date: Mon, 3 Oct 2011 09:13:45 -0400 Subject: drm/radeon/kms: fix regression in DP aux defer handling An incorrect ordering in the error checking code lead to DP aux defer being skipped in the aux native write path. Move the bytes transferred check (ret == 0) below the defer check. Tracked down by: Brad Campbell Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=41121 Signed-off-by: Alex Deucher Cc: Brad Campbell Cc: stable@kernel.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/atombios_dp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/radeon/atombios_dp.c') diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 7ad43c6b1db7..f526fa77e320 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -158,14 +158,14 @@ static int radeon_dp_aux_native_read(struct radeon_connector *radeon_connector, while (1) { ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus, msg, msg_bytes, recv, recv_bytes, delay, &ack); - if (ret == 0) - return -EPROTO; if (ret < 0) return ret; if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) return ret; else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER) udelay(400); + else if (ret == 0) + return -EPROTO; else return -EIO; } -- cgit v1.2.1 From 6375bda073724ead7df08746866b724b1799a295 Mon Sep 17 00:00:00 2001 From: Alex Deucher Date: Mon, 3 Oct 2011 09:13:46 -0400 Subject: 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 Signed-off-by: Alex Deucher Cc: Brad Campbell Cc: stable@kernel.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/atombios_dp.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'drivers/gpu/drm/radeon/atombios_dp.c') diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index f526fa77e320..4da23889fea6 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, -- cgit v1.2.1