On 11/15/2016 10:39 PM, Sean Paul wrote:
> On Thu, Nov 3, 2016 at 3:17 AM, Jianqun Xu <jay.xu at rock-chips.com> wrote:
>> Reference from drm_dp_aux description (about transfer):
>> Upon success, the implementation should return the number of payload bytes
>> that were transferred, or a negative error-code on failure. Helpers
>> propagate errors from the .transfer() function, with the exception of
>> the -EBUSY error, which causes a transaction to be retried. On a short,
>> helpers will return -EPROTO to make it simpler to check for failure.
>>
>> The analogix_dp_transfer will return num_transferred, but if there is none
>> byte been transferred, the return value will be 0, which means success, we
>> should return error-code if transfer none byte.
>>
>> for (retry = 0; retry < 32; retry++) {
>> err = aux->transfer(aux, &msg);
>> if (err < 0) {
>> if (err == -EBUSY)
>> continue;
>>
>> goto unlock;
>> }
>> }
>>
>> Cc: zain wang <wzz at rock-chips.com>
>> Cc: Sean Paul <seanpaul at chromium.org>
>> Signed-off-by: Jianqun Xu <jay.xu at rock-chips.com>
>
> Reviewed-by: Sean Paul <seanpaul at chromium.org>
queued to drm-misc.
>
>> ---
>> drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>> index cd37ac0..303083a 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>> @@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
>> (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
>> msg->reply = DP_AUX_NATIVE_REPLY_ACK;
>>
>> - return num_transferred;
>> + return num_transferred > 0 ? num_transferred : -EBUSY;
>> }
>> --
>> 1.9.1
>>
>>
--
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