Re: Radeon regression fix

[Brad Campbell]

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);
One problem with that logic I'm afraid.

                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;
        }

ret == 0 with a defer as there is no data in the packet. It never even gets past the first hurdle.


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