Re: [PATCH v9 21/22] drm/mediatek: change the aux retries times when receiving AUX_DEFER

On Mon, 2022-03-28 at 00:39 +0200, Guillaume Ranquet wrote:

From: Jitao Shi jitao.shi@mediatek.com

DP 1.4a Section 2.8.7.1.5.6.1: A DP Source device shall retry at least seven times upon receiving AUX_DEFER before giving up the AUX transaction.

Aux should retry to send msg whether how many bytes.

Signed-off-by: Jitao Shi jitao.shi@mediatek.com Signed-off-by: Guillaume Ranquet granquet@baylibre.com

---

drivers/gpu/drm/mediatek/mtk_dp.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index e099491cc6a4..7a197c4a7143 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -2016,7 +2016,7 @@ static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux, bool is_read; u8 request; size_t accessed_bytes = 0;

• int retry = 3, ret = 0;

• int retry, ret = 0;

  mtk_dp = container_of(mtk_aux, struct mtk_dp, aux);

@@ -2050,14 +2050,21 @@ static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux, }

if (msg->size == 0) {

• ret = mtk_dp_aux_do_transfer(mtk_dp, is_read, request,
  

• 			     msg->address +
  

accessed_bytes,

• 			     msg->buffer +
  

accessed_bytes, 0);

• retry = 32;
  

• while (retry--) {
  

• 	ret = mtk_dp_aux_do_transfer(mtk_dp, is_read,
  

request,

• 				     msg->address +
  

accessed_bytes,

• 				     msg->buffer +
  

accessed_bytes, 0);

• 	if (ret == 0)
  

• 		break;
  

• 	usleep_range(500, 600);
  

• }
  

  } else { while (accessed_bytes < msg->size) { size_t to_access = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES, msg->size - accessed_bytes);

• 	retry = 32;
  while (retry--) {
  	ret = mtk_dp_aux_do_transfer(mtk_dp,
  				     is_read,
  

request, @@ -2066,7 +2073,7 @@ static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux, to_access) ; if (ret == 0) break;

• 		usleep_range(50, 100);
  

• 		usleep_range(500, 600);
  }
  if (!retry || ret) {
  	drm_info(mtk_dp->drm_dev,
  

Reviewed-by: Rex-BC Chen rex-bc.chen@mediatek.com