Re: Radeon regression fix

[Brad Campbell]

On 29/09/11 23:21, Brad Campbell wrote:
> 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?

Looking at it with a nights sleep, it's obvious the code path in 
aux_native_write is ok. Is this a bit cleaner than the last patch?

diff --git a/drivers/gpu/drm/radeon/atombios_dp.c 
b/drivers/gpu/drm/radeon/atombios_dp.c
index 7ad43c6..aacc97d 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -158,14 +158,17 @@ 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)
+               if (ret == 0){
+                       if ((ack & AUX_NATIVE_REPLY_MASK) == 
AUX_NATIVE_REPLY_DEFER){
+                               udelay(400);
+                               continue;
+                       }
                        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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