[PATCH 1/2] drm/dp: retry AUX transactions 32 times

Dave Airlie airlied at gmail.com
Tue Nov 25 19:22:40 PST 2014


On 26 November 2014 at 13:20, Tom Stellard <tom at stellard.net> wrote:
> On Wed, Nov 26, 2014 at 01:17:22PM +1000, Dave Airlie wrote:
>> From: Dave Airlie <airlied at redhat.com>
>>
>> At least on two MST devices I've tested with, when
>> they are link training downstream, they are totally
>> unable to handle aux ch msgs, so they defer like nuts.
>> I tried 16, it wasn't enough, 32 seems better.
>>
>> This fixes one Dell 4k monitor and one of the
>> MST hubs.
>>
>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>> ---
>>  drivers/gpu/drm/drm_dp_helper.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
>> index 959e207..db0993f 100644
>> --- a/drivers/gpu/drm/drm_dp_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_helper.c
>> @@ -189,7 +189,7 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
>>        * retry native transactions, so retry 7 times like for I2C-over-AUX
>
> Should this comment be updated too?

Yes it should, good catch!

Thanks,
Dave.


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