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

Guillaume Ranquet
2022-03-27T22:53:01Z

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,
--
2.34.1