diff mbox series

drm/mediatek: dp: change the aux retries times when receiving AUX_DEFER

Message ID 1680072203-10394-1-git-send-email-xinlei.lee@mediatek.com (mailing list archive)
State New, archived
Headers show
Series drm/mediatek: dp: change the aux retries times when receiving AUX_DEFER | expand

Commit Message

Xinlei Lee (李昕磊) March 29, 2023, 6:43 a.m. UTC 
From: Xinlei Lee <xinlei.lee@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.

The drm_dp_i2c_do_msg() function in the drm_dp_helper.c file will
judge the status of the msg->reply parameter passed to aux_transfer
ange-the-aux-retries-times-when-re.patchfor different processing.

Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dp.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Comments

Chun-Kuang Hu April 3, 2023, 3:49 a.m. UTC | #1 
Hi, Xinlei:

<xinlei.lee@mediatek.com> 於 2023年3月29日 週三 下午2:43寫道：
>
> From: Xinlei Lee <xinlei.lee@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.
>
> The drm_dp_i2c_do_msg() function in the drm_dp_helper.c file will
> judge the status of the msg->reply parameter passed to aux_transfer
> ange-the-aux-retries-times-when-re.patchfor different processing.
>
> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dp.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 1f94fcc144d3..767b71da31a4 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -806,10 +806,9 @@ static int mtk_dp_aux_wait_for_completion(struct mtk_dp *mtk_dp, bool is_read)
>  }
>
>  static int mtk_dp_aux_do_transfer(struct mtk_dp *mtk_dp, bool is_read, u8 cmd,
> -                                 u32 addr, u8 *buf, size_t length)
> +                                 u32 addr, u8 *buf, size_t length, u8 *reply_cmd)
>  {
>         int ret;
> -       u32 reply_cmd;
>
>         if (is_read && (length > DP_AUX_MAX_PAYLOAD_BYTES ||
>                         (cmd == DP_AUX_NATIVE_READ && !length)))
> @@ -841,10 +840,10 @@ static int mtk_dp_aux_do_transfer(struct mtk_dp *mtk_dp, bool is_read, u8 cmd,
>         /* Wait for feedback from sink device. */
>         ret = mtk_dp_aux_wait_for_completion(mtk_dp, is_read);
>
> -       reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
> -                   AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
> +       *reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
> +                    AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
>
> -       if (ret || reply_cmd) {
> +       if (ret) {
>                 u32 phy_status = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3628) &
>                                  AUX_RX_PHY_STATE_AUX_TX_P0_MASK;
>                 if (phy_status != AUX_RX_PHY_STATE_AUX_TX_P0_RX_IDLE) {
> @@ -2070,7 +2069,7 @@ static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux,
>                 ret = mtk_dp_aux_do_transfer(mtk_dp, is_read, request,
>                                              msg->address + accessed_bytes,
>                                              msg->buffer + accessed_bytes,
> -                                            to_access);
> +                                            to_access, &msg->reply);
>
>                 if (ret) {
>                         drm_info(mtk_dp->drm_dev,
> @@ -2080,7 +2079,6 @@ static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux,
>                 accessed_bytes += to_access;
>         } while (accessed_bytes < msg->size);
>
> -       msg->reply = DP_AUX_NATIVE_REPLY_ACK | DP_AUX_I2C_REPLY_ACK;

In your description, you just mention the retry count is 7 times, but
you does not mention you should change the reply. Why you modify this?
And where is the 7 times retry?

Regards,
Chun-Kuang.

>         return msg->size;
>  err:
>         msg->reply = DP_AUX_NATIVE_REPLY_NACK | DP_AUX_I2C_REPLY_NACK;
> --
> 2.18.0
>
Xinlei Lee (李昕磊) April 3, 2023, 9:17 a.m. UTC | #2 
On Mon, 2023-04-03 at 11:49 +0800, Chun-Kuang Hu wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Hi, Xinlei:
> 
> <xinlei.lee@mediatek.com> 於 2023年3月29日 週三 下午2:43寫道：
> > 
> > From: Xinlei Lee <xinlei.lee@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.
> > 
> > The drm_dp_i2c_do_msg() function in the drm_dp_helper.c file will
> > judge the status of the msg->reply parameter passed to aux_transfer
> > ange-the-aux-retries-times-when-re.patchfor different processing.
> > 
> > Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort
> > driver")
> > Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dp.c | 12 +++++-------
> >  1 file changed, 5 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c
> > b/drivers/gpu/drm/mediatek/mtk_dp.c
> > index 1f94fcc144d3..767b71da31a4 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> > @@ -806,10 +806,9 @@ static int
> > mtk_dp_aux_wait_for_completion(struct mtk_dp *mtk_dp, bool is_read)
> >  }
> > 
> >  static int mtk_dp_aux_do_transfer(struct mtk_dp *mtk_dp, bool
> > is_read, u8 cmd,
> > -                                 u32 addr, u8 *buf, size_t length)
> > +                                 u32 addr, u8 *buf, size_t length,
> > u8 *reply_cmd)
> >  {
> >         int ret;
> > -       u32 reply_cmd;
> > 
> >         if (is_read && (length > DP_AUX_MAX_PAYLOAD_BYTES ||
> >                         (cmd == DP_AUX_NATIVE_READ && !length)))
> > @@ -841,10 +840,10 @@ static int mtk_dp_aux_do_transfer(struct
> > mtk_dp *mtk_dp, bool is_read, u8 cmd,
> >         /* Wait for feedback from sink device. */
> >         ret = mtk_dp_aux_wait_for_completion(mtk_dp, is_read);
> > 
> > -       reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
> > -                   AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
> > +       *reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
> > +                    AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
> > 
> > -       if (ret || reply_cmd) {
> > +       if (ret) {
> >                 u32 phy_status = mtk_dp_read(mtk_dp,
> > MTK_DP_AUX_P0_3628) &
> >                                  AUX_RX_PHY_STATE_AUX_TX_P0_MASK;
> >                 if (phy_status !=
> > AUX_RX_PHY_STATE_AUX_TX_P0_RX_IDLE) {
> > @@ -2070,7 +2069,7 @@ static ssize_t mtk_dp_aux_transfer(struct
> > drm_dp_aux *mtk_aux,
> >                 ret = mtk_dp_aux_do_transfer(mtk_dp, is_read,
> > request,
> >                                              msg->address +
> > accessed_bytes,
> >                                              msg->buffer +
> > accessed_bytes,
> > -                                            to_access);
> > +                                            to_access, &msg-
> > >reply);
> > 
> >                 if (ret) {
> >                         drm_info(mtk_dp->drm_dev,
> > @@ -2080,7 +2079,6 @@ static ssize_t mtk_dp_aux_transfer(struct
> > drm_dp_aux *mtk_aux,
> >                 accessed_bytes += to_access;
> >         } while (accessed_bytes < msg->size);
> > 
> > -       msg->reply = DP_AUX_NATIVE_REPLY_ACK |
> > DP_AUX_I2C_REPLY_ACK;
> 
> In your description, you just mention the retry count is 7 times, but
> you does not mention you should change the reply. Why you modify
> this?
> And where is the 7 times retry?
> 
> Regards,
> Chun-Kuang.
> 
> >         return msg->size;
> >  err:
> >         msg->reply = DP_AUX_NATIVE_REPLY_NACK |
> > DP_AUX_I2C_REPLY_NACK;
> > --
> > 2.18.0
> > 

Hi CK:

Thanks for your review!

This patch is to fix some DP sinks that return AUX_DEFER, and the dp 
driver does not handle it according to the specification. DP_v1.4a
spec 2.8.1.2 describes that if the sink returns AUX_DEFER, DPTX may 
retry later:

The logic before the modification is that reply_cmd returns ETIMEDOUT 
if it is not AUX_ACK after the read operation, without considering the 
retry operation when returning AUX_DEFER;

The modified logic is to add parameters to mtk_dp_aux_do_transfer() to 
store the return value of the sink. In the dmr_dp_helper.c file, 
drm_dp_i2c_do_msg calls aux->transfer and then performs retry
operation according to msg->reply. The 7 times specified in the spec 
are also in this function defined in (max_retries).

Best Regards!
xinlei
Chun-Kuang Hu April 3, 2023, 4:55 p.m. UTC | #3 
Hi, Xinlei:

Xinlei Lee (李昕磊) <Xinlei.Lee@mediatek.com> 於 2023年4月3日 週一 下午5:18寫道：
>
> On Mon, 2023-04-03 at 11:49 +0800, Chun-Kuang Hu wrote:
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >
> >
> > Hi, Xinlei:
> >
> > <xinlei.lee@mediatek.com> 於 2023年3月29日 週三 下午2:43寫道：
> > >
> > > From: Xinlei Lee <xinlei.lee@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.
> > >
> > > The drm_dp_i2c_do_msg() function in the drm_dp_helper.c file will
> > > judge the status of the msg->reply parameter passed to aux_transfer
> > > ange-the-aux-retries-times-when-re.patchfor different processing.
> > >
> > > Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort
> > > driver")
> > > Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> > > ---
> > >  drivers/gpu/drm/mediatek/mtk_dp.c | 12 +++++-------
> > >  1 file changed, 5 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c
> > > b/drivers/gpu/drm/mediatek/mtk_dp.c
> > > index 1f94fcc144d3..767b71da31a4 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> > > @@ -806,10 +806,9 @@ static int
> > > mtk_dp_aux_wait_for_completion(struct mtk_dp *mtk_dp, bool is_read)
> > >  }
> > >
> > >  static int mtk_dp_aux_do_transfer(struct mtk_dp *mtk_dp, bool
> > > is_read, u8 cmd,
> > > -                                 u32 addr, u8 *buf, size_t length)
> > > +                                 u32 addr, u8 *buf, size_t length,
> > > u8 *reply_cmd)
> > >  {
> > >         int ret;
> > > -       u32 reply_cmd;
> > >
> > >         if (is_read && (length > DP_AUX_MAX_PAYLOAD_BYTES ||
> > >                         (cmd == DP_AUX_NATIVE_READ && !length)))
> > > @@ -841,10 +840,10 @@ static int mtk_dp_aux_do_transfer(struct
> > > mtk_dp *mtk_dp, bool is_read, u8 cmd,
> > >         /* Wait for feedback from sink device. */
> > >         ret = mtk_dp_aux_wait_for_completion(mtk_dp, is_read);
> > >
> > > -       reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
> > > -                   AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
> > > +       *reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
> > > +                    AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
> > >
> > > -       if (ret || reply_cmd) {
> > > +       if (ret) {
> > >                 u32 phy_status = mtk_dp_read(mtk_dp,
> > > MTK_DP_AUX_P0_3628) &
> > >                                  AUX_RX_PHY_STATE_AUX_TX_P0_MASK;
> > >                 if (phy_status !=
> > > AUX_RX_PHY_STATE_AUX_TX_P0_RX_IDLE) {
> > > @@ -2070,7 +2069,7 @@ static ssize_t mtk_dp_aux_transfer(struct
> > > drm_dp_aux *mtk_aux,
> > >                 ret = mtk_dp_aux_do_transfer(mtk_dp, is_read,
> > > request,
> > >                                              msg->address +
> > > accessed_bytes,
> > >                                              msg->buffer +
> > > accessed_bytes,
> > > -                                            to_access);
> > > +                                            to_access, &msg-
> > > >reply);
> > >
> > >                 if (ret) {
> > >                         drm_info(mtk_dp->drm_dev,
> > > @@ -2080,7 +2079,6 @@ static ssize_t mtk_dp_aux_transfer(struct
> > > drm_dp_aux *mtk_aux,
> > >                 accessed_bytes += to_access;
> > >         } while (accessed_bytes < msg->size);
> > >
> > > -       msg->reply = DP_AUX_NATIVE_REPLY_ACK |
> > > DP_AUX_I2C_REPLY_ACK;
> >
> > In your description, you just mention the retry count is 7 times, but
> > you does not mention you should change the reply. Why you modify
> > this?
> > And where is the 7 times retry?
> >
> > Regards,
> > Chun-Kuang.
> >
> > >         return msg->size;
> > >  err:
> > >         msg->reply = DP_AUX_NATIVE_REPLY_NACK |
> > > DP_AUX_I2C_REPLY_NACK;
> > > --
> > > 2.18.0
> > >
>
> Hi CK:
>
> Thanks for your review!
>
> This patch is to fix some DP sinks that return AUX_DEFER, and the dp
> driver does not handle it according to the specification. DP_v1.4a
> spec 2.8.1.2 describes that if the sink returns AUX_DEFER, DPTX may
> retry later:
>
> The logic before the modification is that reply_cmd returns ETIMEDOUT
> if it is not AUX_ACK after the read operation, without considering the
> retry operation when returning AUX_DEFER;
>
> The modified logic is to add parameters to mtk_dp_aux_do_transfer() to
> store the return value of the sink. In the dmr_dp_helper.c file,
> drm_dp_i2c_do_msg calls aux->transfer and then performs retry
> operation according to msg->reply. The 7 times specified in the spec
> are also in this function defined in (max_retries).

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

>
> Best Regards!
> xinlei
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
index 1f94fcc144d3..767b71da31a4 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -806,10 +806,9 @@  static int mtk_dp_aux_wait_for_completion(struct mtk_dp *mtk_dp, bool is_read)
 }
 
 static int mtk_dp_aux_do_transfer(struct mtk_dp *mtk_dp, bool is_read, u8 cmd,
-				  u32 addr, u8 *buf, size_t length)
+				  u32 addr, u8 *buf, size_t length, u8 *reply_cmd)
 {
 	int ret;
-	u32 reply_cmd;
 
 	if (is_read && (length > DP_AUX_MAX_PAYLOAD_BYTES ||
 			(cmd == DP_AUX_NATIVE_READ && !length)))
@@ -841,10 +840,10 @@  static int mtk_dp_aux_do_transfer(struct mtk_dp *mtk_dp, bool is_read, u8 cmd,
 	/* Wait for feedback from sink device. */
 	ret = mtk_dp_aux_wait_for_completion(mtk_dp, is_read);
 
-	reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
-		    AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
+	*reply_cmd = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3624) &
+		     AUX_RX_REPLY_COMMAND_AUX_TX_P0_MASK;
 
-	if (ret || reply_cmd) {
+	if (ret) {
 		u32 phy_status = mtk_dp_read(mtk_dp, MTK_DP_AUX_P0_3628) &
 				 AUX_RX_PHY_STATE_AUX_TX_P0_MASK;
 		if (phy_status != AUX_RX_PHY_STATE_AUX_TX_P0_RX_IDLE) {
@@ -2070,7 +2069,7 @@  static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux,
 		ret = mtk_dp_aux_do_transfer(mtk_dp, is_read, request,
 					     msg->address + accessed_bytes,
 					     msg->buffer + accessed_bytes,
-					     to_access);
+					     to_access, &msg->reply);
 
 		if (ret) {
 			drm_info(mtk_dp->drm_dev,
@@ -2080,7 +2079,6 @@  static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux,
 		accessed_bytes += to_access;
 	} while (accessed_bytes < msg->size);
 
-	msg->reply = DP_AUX_NATIVE_REPLY_ACK | DP_AUX_I2C_REPLY_ACK;
 	return msg->size;
 err:
 	msg->reply = DP_AUX_NATIVE_REPLY_NACK | DP_AUX_I2C_REPLY_NACK;