Re: Radeon regression fix

From: Brad Campbell
Date: Thu Sep 29 2011 - 11:21:12 EST


On 29/09/11 22:36, Alex Deucher wrote:
On Thu, Sep 29, 2011 at 10:21 AM, Brad Campbell<brad@xxxxxxxxxxxxxxx> wrote:
This patch fixes a regression introduced between 2.6.39& 3.1-rc1 whereby
the displayport AUX channel stopped re-trying commands that elicited a DEFER
response.


It should still be retrying, just restructured slightly. The retry
logic just moved into radeon_dp_i2c_aux_ch(),
radeon_dp_aux_native_write(), and radeon_dp_aux_native_read(), e.g.,

else if ((ack& AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
udelay(400);

Perhaps the delay is causing a problem. Does removing the udelay(400); help?

How's this look ?


diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 7ad43c6..aa5624a 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -128,12 +128,14 @@ static int radeon_dp_aux_native_write(struct radeon_connector *radeon_connector,
while (1) {
ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus,
msg, msg_bytes, NULL, 0, delay, &ack);
+ if (ret == 0 && ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)){
+ udelay(400);
+ continue;
+ }
if (ret < 0)
return ret;
if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK)
break;
- else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
- udelay(400);
else
return -EIO;
}
@@ -158,14 +160,16 @@ 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 && ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)){
+ udelay(400);
+ continue;
+ }
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
return -EIO;
}
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