[PATCH 1/4] drm/radeon/dp: handle zero sized i2c over aux transactions

[Alex Deucher]

On Sat, Apr 5, 2014 at 5:25 AM, Christian König <deathsimple at vodafone.de> wrote:
> Am 04.04.2014 21:58, schrieb Alex Deucher:
>
>> Needed for proper i2c over aux handling for certain
>> monitors and configurations (e.g., dp bridges or
>> adapters).
>>
>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>
>
> My planning was that yesterdays pull request is the last one with new
> features. I can't judge how invasive this series is, so should I add it to
> my 3.15 branch and send Dave another pull request or should we wait for
> 3.16?

I'd like to get them into 3.15.  They provide a really nice cleanup
for the radeon dp i2c handling.

Alex

>
> Christian.
>
>
>> ---
>>   drivers/gpu/drm/radeon/atombios_dp.c | 15 +++++++++++----
>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/radeon/atombios_dp.c
>> b/drivers/gpu/drm/radeon/atombios_dp.c
>> index 8b0ab17..e914008 100644
>> --- a/drivers/gpu/drm/radeon/atombios_dp.c
>> +++ b/drivers/gpu/drm/radeon/atombios_dp.c
>> @@ -143,6 +143,7 @@ static int radeon_process_aux_ch(struct
>> radeon_i2c_chan *chan,
>>   }
>>     #define HEADER_SIZE 4
>> +#define BARE_ADDRESS_SIZE 3
>>     static ssize_t
>>   radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg
>> *msg)
>> @@ -160,13 +161,16 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux,
>> struct drm_dp_aux_msg *msg)
>>         tx_buf[0] = msg->address & 0xff;
>>         tx_buf[1] = msg->address >> 8;
>>         tx_buf[2] = msg->request << 4;
>> -       tx_buf[3] = msg->size - 1;
>> +       tx_buf[3] = msg->size ? (msg->size - 1) : 0;
>>         switch (msg->request & ~DP_AUX_I2C_MOT) {
>>         case DP_AUX_NATIVE_WRITE:
>>         case DP_AUX_I2C_WRITE:
>>                 tx_size = HEADER_SIZE + msg->size;
>> -               tx_buf[3] |= tx_size << 4;
>> +               if (msg->size == 0)
>> +                       tx_buf[3] |= BARE_ADDRESS_SIZE << 4;
>> +               else
>> +                       tx_buf[3] |= tx_size << 4;
>>                 memcpy(tx_buf + HEADER_SIZE, msg->buffer, msg->size);
>>                 ret = radeon_process_aux_ch(chan,
>>                                             tx_buf, tx_size, NULL, 0,
>> delay, &ack);
>> @@ -177,7 +181,10 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct
>> drm_dp_aux_msg *msg)
>>         case DP_AUX_NATIVE_READ:
>>         case DP_AUX_I2C_READ:
>>                 tx_size = HEADER_SIZE;
>> -               tx_buf[3] |= tx_size << 4;
>> +               if (msg->size == 0)
>> +                       tx_buf[3] |= BARE_ADDRESS_SIZE << 4;
>> +               else
>> +                       tx_buf[3] |= tx_size << 4;
>>                 ret = radeon_process_aux_ch(chan,
>>                                             tx_buf, tx_size, msg->buffer,
>> msg->size, delay, &ack);
>>                 break;
>> @@ -186,7 +193,7 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct
>> drm_dp_aux_msg *msg)
>>                 break;
>>         }
>>   -     if (ret > 0)
>> +       if (ret >= 0)
>>                 msg->reply = ack >> 4;
>>         return ret;
>
>