On Thu, Sep 29, 2011 at 8:23 PM, Brad Campbell
<lists2009@xxxxxxxxxxxxxxx> wrote:
> 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?
Looks pretty good. I was thinking of something more like this (sorry
for the lack of a patch, I'm away from my source trees at the moment):
while (1) {
ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus,
msg, msg_bytes, recv, recv_bytes, delay, &ack);
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;
}
Thanks for tracking this down.
Alex
>
> 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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