2022-08-02 07:36:51

by Heikki Krogerus

[permalink] [raw]
Subject: Re: [PATCH] usb: typec: altmodes/displayport: correct pin assignment for UFP receptacles

Hi guys,

On Wed, Jul 27, 2022 at 07:05:03PM +0800, Macpaul Lin wrote:
> From: Pablo Sun <[email protected]>
>
> From: Pablo Sun <[email protected]>

Looks like there's something wrong with the formating of the patch
here?

> Fix incorrect pin assignment values when connecting to a monitor with
> Type-C receptacle instead of a plug.
>
> According to specification, an UFP_D receptacle's pin assignment
> should came from the UFP_D pin assignments field (bit 23:16), while
> an UFP_D plug's assignments are described in the DFP_D pin assignments
> (bit 15:8) during Mode Discovery.
>
> For example the LG 27 UL850-W is a monitor with Type-C receptacle.
> The monitor responds to MODE DISCOVERY command with following
> DisplayPort Capability flag:
>
> dp->alt->vdo=0x140045
>
> The existing logic only take cares of UPF_D plug case,
> and would take the bit 15:8 for this 0x140045 case.
>
> This results in an non-existing pin assignment 0x0 in
> dp_altmode_configure.
>
> To fix this problem a new set of macros are introduced
> to take plug/receptacle differences into consideration.
>
> Co-developed-by: Pablo Sun <[email protected]>
> Signed-off-by: Pablo Sun <[email protected]>
> Co-developed-by: Macpaul Lin <[email protected]>
> Signed-off-by: Macpaul Lin <[email protected]>
> Reviewed-by: Guillaume Ranquet <[email protected]>
> Cc: [email protected]

If this is a fix, then you need to have the "Fixes" tag that tells
which commit the patch is fixing.

> ---
> drivers/usb/typec/altmodes/displayport.c | 4 ++--
> include/linux/usb/typec_dp.h | 5 +++++
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index 9360ca177c7d..8dd0e505ef99 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -98,8 +98,8 @@ static int dp_altmode_configure(struct dp_altmode *dp, u8 con)
> case DP_STATUS_CON_UFP_D:
> case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */
> conf |= DP_CONF_UFP_U_AS_UFP_D;
> - pin_assign = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo) &
> - DP_CAP_UFP_D_PIN_ASSIGN(dp->port->vdo);
> + pin_assign = DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo) &
> + DP_CAP_PIN_ASSIGN_DFP_D(dp->port->vdo);
> break;
> default:
> break;
> diff --git a/include/linux/usb/typec_dp.h b/include/linux/usb/typec_dp.h
> index cfb916cccd31..8d09c2f0a9b8 100644
> --- a/include/linux/usb/typec_dp.h
> +++ b/include/linux/usb/typec_dp.h
> @@ -73,6 +73,11 @@ enum {
> #define DP_CAP_USB BIT(7)
> #define DP_CAP_DFP_D_PIN_ASSIGN(_cap_) (((_cap_) & GENMASK(15, 8)) >> 8)
> #define DP_CAP_UFP_D_PIN_ASSIGN(_cap_) (((_cap_) & GENMASK(23, 16)) >> 16)
> +/* Get pin assignment taking plug & receptacle into consideration */
> +#define DP_CAP_PIN_ASSIGN_UFP_D(_cap_) ((_cap_ & DP_CAP_RECEPTACLE) ? \
> + DP_CAP_UFP_D_PIN_ASSIGN(_cap_) : DP_CAP_DFP_D_PIN_ASSIGN(_cap_))
> +#define DP_CAP_PIN_ASSIGN_DFP_D(_cap_) ((_cap_ & DP_CAP_RECEPTACLE) ? \
> + DP_CAP_DFP_D_PIN_ASSIGN(_cap_) : DP_CAP_UFP_D_PIN_ASSIGN(_cap_))
>
> /* DisplayPort Status Update VDO bits */
> #define DP_STATUS_CONNECTION(_status_) ((_status_) & 3)
> --
> 2.18.0

thanks,

--
heikki


2022-08-04 02:44:35

by Macpaul Lin

[permalink] [raw]
Subject: Re: [PATCH] usb: typec: altmodes/displayport: correct pin assignment for UFP receptacles

On 8/2/22 3:28 PM, Heikki Krogerus wrote:
> Hi guys,
>
> On Wed, Jul 27, 2022 at 07:05:03PM +0800, Macpaul Lin wrote:
>> From: Pablo Sun <[email protected]>
>>
>> From: Pablo Sun <[email protected]>
>
> Looks like there's something wrong with the formating of the patch
> here?

The duplicated line will be removed in patch v2.

>> Fix incorrect pin assignment values when connecting to a monitor with
>> Type-C receptacle instead of a plug.
>>
>> According to specification, an UFP_D receptacle's pin assignment
>> should came from the UFP_D pin assignments field (bit 23:16), while
>> an UFP_D plug's assignments are described in the DFP_D pin assignments
>> (bit 15:8) during Mode Discovery.
>>
>> For example the LG 27 UL850-W is a monitor with Type-C receptacle.
>> The monitor responds to MODE DISCOVERY command with following
>> DisplayPort Capability flag:
>>
>> dp->alt->vdo=0x140045
>>
>> The existing logic only take cares of UPF_D plug case,
>> and would take the bit 15:8 for this 0x140045 case.
>>
>> This results in an non-existing pin assignment 0x0 in
>> dp_altmode_configure.
>>
>> To fix this problem a new set of macros are introduced
>> to take plug/receptacle differences into consideration.
>>
>> Co-developed-by: Pablo Sun <[email protected]>
>> Signed-off-by: Pablo Sun <[email protected]>
>> Co-developed-by: Macpaul Lin <[email protected]>
>> Signed-off-by: Macpaul Lin <[email protected]>
>> Reviewed-by: Guillaume Ranquet <[email protected]>
>> Cc: [email protected]
>
> If this is a fix, then you need to have the "Fixes" tag that tells
> which commit the patch is fixing.

Thanks for the review.
Will add "Fixes" tag and "Reviewed-by" tags in patch v2.

>> ---
>> drivers/usb/typec/altmodes/displayport.c | 4 ++--
>> include/linux/usb/typec_dp.h | 5 +++++
>> 2 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/typec/altmodes/displayport.c
b/drivers/usb/typec/altmodes/displayport.c
>> index 9360ca177c7d..8dd0e505ef99 100644
>> --- a/drivers/usb/typec/altmodes/displayport.c
>> +++ b/drivers/usb/typec/altmodes/displayport.c
>> @@ -98,8 +98,8 @@ static int dp_altmode_configure(struct dp_altmode *dp,
u8 con)
>> case DP_STATUS_CON_UFP_D:
>> case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */
>> conf |= DP_CONF_UFP_U_AS_UFP_D;
>> - pin_assign = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo) &
>> - DP_CAP_UFP_D_PIN_ASSIGN(dp->port->vdo);
>> + pin_assign = DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo) &
>> + DP_CAP_PIN_ASSIGN_DFP_D(dp->port->vdo);
>> break;
>> default:
>> break;
>> diff --git a/include/linux/usb/typec_dp.h b/include/linux/usb/typec_dp.h
>> index cfb916cccd31..8d09c2f0a9b8 100644
>> --- a/include/linux/usb/typec_dp.h
>> +++ b/include/linux/usb/typec_dp.h
>> @@ -73,6 +73,11 @@ enum {
>> #define DP_CAP_USB BIT(7)
>> #define DP_CAP_DFP_D_PIN_ASSIGN(_cap_) (((_cap_) & GENMASK(15, 8)) >>
8)
>> #define DP_CAP_UFP_D_PIN_ASSIGN(_cap_) (((_cap_) & GENMASK(23, 16)) >>
16)
>> +/* Get pin assignment taking plug & receptacle into consideration */
>> +#define DP_CAP_PIN_ASSIGN_UFP_D(_cap_) ((_cap_ & DP_CAP_RECEPTACLE) ? \
>> + DP_CAP_UFP_D_PIN_ASSIGN(_cap_) : DP_CAP_DFP_D_PIN_ASSIGN(_cap_))
>> +#define DP_CAP_PIN_ASSIGN_DFP_D(_cap_) ((_cap_ & DP_CAP_RECEPTACLE) ? \
>> + DP_CAP_DFP_D_PIN_ASSIGN(_cap_) : DP_CAP_UFP_D_PIN_ASSIGN(_cap_))
>>
>> /* DisplayPort Status Update VDO bits */
>> #define DP_STATUS_CONNECTION(_status_) ((_status_) & 3)
>> --
>> 2.18.0
>
> thanks,
>

Thanks.
Macpaul Lin