[PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Khaled Almahallawy]

The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3 spec.
Update its name to align with the DP 2.1 definition and reflect its
actual use in the code. No functional changes.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rob Clark <robin.clark@oss.qualcomm.com>
Cc: Dmitry Baryshkov <lumag@kernel.org>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Sean Paul <sean@poorly.run>
Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
---
 drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
 include/drm/display/drm_dp.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
index 66e1bbd80db3..5d465cf4dbc2 100644
--- a/drivers/gpu/drm/msm/dp/dp_link.c
+++ b/drivers/gpu/drm/msm/dp/dp_link.c
@@ -665,7 +665,7 @@ static int msm_dp_link_parse_request(struct msm_dp_link_private *link)
 		return rlen;
 	}
 
-	if (!data || (data == DP_TEST_LINK_FAUX_PATTERN)) {
+	if (!data || (data == DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE)) {
 		drm_dbg_dp(link->drm_dev, "link 0x%x not supported\n", data);
 		goto end;
 	}
diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
index e4eebabab975..610b8cbf1125 100644
--- a/include/drm/display/drm_dp.h
+++ b/include/drm/display/drm_dp.h
@@ -849,7 +849,7 @@
 # define DP_TEST_LINK_VIDEO_PATTERN	    (1 << 1)
 # define DP_TEST_LINK_EDID_READ		    (1 << 2)
 # define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >= 1.1 */
-# define DP_TEST_LINK_FAUX_PATTERN	    (1 << 4) /* DPCD >= 1.2 */
+# define DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE	    (1 << 4)
 # define DP_TEST_LINK_AUDIO_PATTERN         (1 << 5) /* DPCD >= 1.2 */
 # define DP_TEST_LINK_AUDIO_DISABLED_VIDEO  (1 << 6) /* DPCD >= 1.2 */
 
-- 
2.43.0

Re: [PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Dmitry Baryshkov]

On Tue, Oct 28, 2025 at 03:28:17PM -0700, Khaled Almahallawy wrote:
> The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3 spec.
> Update its name to align with the DP 2.1 definition and reflect its
> actual use in the code. No functional changes.
> 
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Rob Clark <robin.clark@oss.qualcomm.com>
> Cc: Dmitry Baryshkov <lumag@kernel.org>
> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> Cc: Sean Paul <sean@poorly.run>
> Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
>  include/drm/display/drm_dp.h     | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Would you prefer to merge this through drm-misc-next or through msm-next?

-- 
With best wishes
Dmitry

Re: [PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Konrad Dybcio]

On 10/28/25 11:28 PM, Khaled Almahallawy wrote:
> The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3 spec.
> Update its name to align with the DP 2.1 definition and reflect its
> actual use in the code. No functional changes.
> 
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Rob Clark <robin.clark@oss.qualcomm.com>
> Cc: Dmitry Baryshkov <lumag@kernel.org>
> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> Cc: Sean Paul <sean@poorly.run>
> Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
>  include/drm/display/drm_dp.h     | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
> index 66e1bbd80db3..5d465cf4dbc2 100644
> --- a/drivers/gpu/drm/msm/dp/dp_link.c
> +++ b/drivers/gpu/drm/msm/dp/dp_link.c
> @@ -665,7 +665,7 @@ static int msm_dp_link_parse_request(struct msm_dp_link_private *link)
>  		return rlen;
>  	}
>  
> -	if (!data || (data == DP_TEST_LINK_FAUX_PATTERN)) {
> +	if (!data || (data == DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE)) {
>  		drm_dbg_dp(link->drm_dev, "link 0x%x not supported\n", data);
>  		goto end;
>  	}
> diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
> index e4eebabab975..610b8cbf1125 100644
> --- a/include/drm/display/drm_dp.h
> +++ b/include/drm/display/drm_dp.h
> @@ -849,7 +849,7 @@
>  # define DP_TEST_LINK_VIDEO_PATTERN	    (1 << 1)
>  # define DP_TEST_LINK_EDID_READ		    (1 << 2)
>  # define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >= 1.1 */
> -# define DP_TEST_LINK_FAUX_PATTERN	    (1 << 4) /* DPCD >= 1.2 */
> +# define DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE	    (1 << 4)

I think it'd be useful to keep a comment of what it was before the
deprecation and rename

Konrad

Re: [PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Almahallawy, Khaled]

On Wed, 2025-10-29 at 10:42 +0100, Konrad Dybcio wrote:
> On 10/28/25 11:28 PM, Khaled Almahallawy wrote:
> > The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3
> > spec.
> > Update its name to align with the DP 2.1 definition and reflect its
> > actual use in the code. No functional changes.
> > 
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Rob Clark <robin.clark@oss.qualcomm.com>
> > Cc: Dmitry Baryshkov <lumag@kernel.org>
> > Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> > Cc: Sean Paul <sean@poorly.run>
> > Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
> > ---
> >  drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
> >  include/drm/display/drm_dp.h     | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/dp/dp_link.c
> > b/drivers/gpu/drm/msm/dp/dp_link.c
> > index 66e1bbd80db3..5d465cf4dbc2 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_link.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_link.c
> > @@ -665,7 +665,7 @@ static int msm_dp_link_parse_request(struct
> > msm_dp_link_private *link)
> >  		return rlen;
> >  	}
> >  
> > -	if (!data || (data == DP_TEST_LINK_FAUX_PATTERN)) {
> > +	if (!data || (data ==
> > DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE)) {
> >  		drm_dbg_dp(link->drm_dev, "link 0x%x not
> > supported\n", data);
> >  		goto end;
> >  	}
> > diff --git a/include/drm/display/drm_dp.h
> > b/include/drm/display/drm_dp.h
> > index e4eebabab975..610b8cbf1125 100644
> > --- a/include/drm/display/drm_dp.h
> > +++ b/include/drm/display/drm_dp.h
> > @@ -849,7 +849,7 @@
> >  # define DP_TEST_LINK_VIDEO_PATTERN	    (1 << 1)
> >  # define DP_TEST_LINK_EDID_READ		    (1 << 2)
> >  # define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >=
> > 1.1 */
> > -# define DP_TEST_LINK_FAUX_PATTERN	    (1 << 4) /* DPCD >=
> > 1.2 */
> > +# define DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE	    (1 << 4)
> 
> I think it'd be useful to keep a comment of what it was before the
> deprecation and rename

Given that msm is currently the only driver that reads this bit and
correctly interprets it when handling automated test requests to
determine 128b/132b support—and following the style used throughout
this file, since I don’t see other examples referencing deprecated
names in comments

what do you think about using something like this instead?

#define DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE  (1 << 4) /* DP 2.1 */

Thank You
Khaled
> 
> Konrad

Re: [PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Almahallawy, Khaled]

On Wed, 2025-10-29 at 10:57 +0200, Dmitry Baryshkov wrote:
> On Tue, Oct 28, 2025 at 03:28:17PM -0700, Khaled Almahallawy wrote:
> > The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3
> > spec.
> > Update its name to align with the DP 2.1 definition and reflect its
> > actual use in the code. No functional changes.
> > 
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Rob Clark <robin.clark@oss.qualcomm.com>
> > Cc: Dmitry Baryshkov <lumag@kernel.org>
> > Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> > Cc: Sean Paul <sean@poorly.run>
> > Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
> > ---
> >  drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
> >  include/drm/display/drm_dp.h     | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> 
> Would you prefer to merge this through drm-misc-next or through msm-
> next?

Thank you for your review. 
it would be great if you can merge to drm-misc-next after I address
Konrad input.

Thanks
Khaled
> 

Re: [PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Dmitry Baryshkov]

On Wed, Oct 29, 2025 at 09:43:45PM +0000, Almahallawy, Khaled wrote:
> On Wed, 2025-10-29 at 10:57 +0200, Dmitry Baryshkov wrote:
> > On Tue, Oct 28, 2025 at 03:28:17PM -0700, Khaled Almahallawy wrote:
> > > The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3
> > > spec.
> > > Update its name to align with the DP 2.1 definition and reflect its
> > > actual use in the code. No functional changes.
> > > 
> > > Cc: Jani Nikula <jani.nikula@intel.com>
> > > Cc: Rob Clark <robin.clark@oss.qualcomm.com>
> > > Cc: Dmitry Baryshkov <lumag@kernel.org>
> > > Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> > > Cc: Sean Paul <sean@poorly.run>
> > > Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
> > > ---
> > >  drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
> > >  include/drm/display/drm_dp.h     | 2 +-
> > >  2 files changed, 2 insertions(+), 2 deletions(-)
> > > 
> > 
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> > 
> > Would you prefer to merge this through drm-misc-next or through msm-
> > next?
> 
> Thank you for your review. 
> it would be great if you can merge to drm-misc-next after I address
> Konrad input.

Yes, please send v2 once it's ready.

-- 
With best wishes
Dmitry

Re: [PATCH] drm/display/dp: Rename bit 4 of DPCD TEST_REQUEST to match DP2.1 spec

[Konrad Dybcio]

On 10/29/25 10:42 PM, Almahallawy, Khaled wrote:
> On Wed, 2025-10-29 at 10:42 +0100, Konrad Dybcio wrote:
>> On 10/28/25 11:28 PM, Khaled Almahallawy wrote:
>>> The DP_TEST_LINK_FAUX_PATTERN field was deprecated in the DP 1.3
>>> spec.
>>> Update its name to align with the DP 2.1 definition and reflect its
>>> actual use in the code. No functional changes.
>>>
>>> Cc: Jani Nikula <jani.nikula@intel.com>
>>> Cc: Rob Clark <robin.clark@oss.qualcomm.com>
>>> Cc: Dmitry Baryshkov <lumag@kernel.org>
>>> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
>>> Cc: Sean Paul <sean@poorly.run>
>>> Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
>>> ---
>>>  drivers/gpu/drm/msm/dp/dp_link.c | 2 +-
>>>  include/drm/display/drm_dp.h     | 2 +-
>>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c
>>> b/drivers/gpu/drm/msm/dp/dp_link.c
>>> index 66e1bbd80db3..5d465cf4dbc2 100644
>>> --- a/drivers/gpu/drm/msm/dp/dp_link.c
>>> +++ b/drivers/gpu/drm/msm/dp/dp_link.c
>>> @@ -665,7 +665,7 @@ static int msm_dp_link_parse_request(struct
>>> msm_dp_link_private *link)
>>>  		return rlen;
>>>  	}
>>>  
>>> -	if (!data || (data == DP_TEST_LINK_FAUX_PATTERN)) {
>>> +	if (!data || (data ==
>>> DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE)) {
>>>  		drm_dbg_dp(link->drm_dev, "link 0x%x not
>>> supported\n", data);
>>>  		goto end;
>>>  	}
>>> diff --git a/include/drm/display/drm_dp.h
>>> b/include/drm/display/drm_dp.h
>>> index e4eebabab975..610b8cbf1125 100644
>>> --- a/include/drm/display/drm_dp.h
>>> +++ b/include/drm/display/drm_dp.h
>>> @@ -849,7 +849,7 @@
>>>  # define DP_TEST_LINK_VIDEO_PATTERN	    (1 << 1)
>>>  # define DP_TEST_LINK_EDID_READ		    (1 << 2)
>>>  # define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >=
>>> 1.1 */
>>> -# define DP_TEST_LINK_FAUX_PATTERN	    (1 << 4) /* DPCD >=
>>> 1.2 */
>>> +# define DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE	    (1 << 4)
>>
>> I think it'd be useful to keep a comment of what it was before the
>> deprecation and rename
> 
> Given that msm is currently the only driver that reads this bit and
> correctly interprets it when handling automated test requests to
> determine 128b/132b support—and following the style used throughout
> this file, since I don’t see other examples referencing deprecated
> names in comments
> 
> what do you think about using something like this instead?
> 
> #define DP_TEST_PHY_TEST_CHANNEL_CODING_TYPE  (1 << 4) /* DP 2.1 */

Makes sense, let's do it

Konrad