Hi guys,
On Wed, Jul 27, 2022 at 07:05:03PM +0800, Macpaul Lin wrote:
> From: Pablo Sun <pablo.sun@xxxxxxxxxxxx>
>
> From: Pablo Sun <pablo.sun@xxxxxxxxxxxx>
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 <pablo.sun@xxxxxxxxxxxx>
> Signed-off-by: Pablo Sun <pablo.sun@xxxxxxxxxxxx>
> Co-developed-by: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
> Signed-off-by: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
> Reviewed-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
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
