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  3. [PATCH v6 0/7] VESA DisplayID spec allows the device to force its DSC bits per pixel value.
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[PATCH v6 4/7] drm/edid: parse DSC DPP passthru support flag for mode VII timings

Yaroslav Bolyukin posted 7 patches 5 days, 16 hours ago
[PATCH v6 4/7] drm/edid: parse DSC DPP passthru support flag for mode VII timings
Posted by Yaroslav Bolyukin 5 days, 16 hours ago 
Signed-off-by: Yaroslav Bolyukin <iam@lach.pw>
---
 drivers/gpu/drm/drm_displayid_internal.h |  2 ++
 drivers/gpu/drm/drm_edid.c               | 12 ++++++++----
 include/drm/drm_modes.h                  | 10 ++++++++++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm_displayid_internal.h
index 72f107ae832f..724174b429f2 100644
--- a/drivers/gpu/drm/drm_displayid_internal.h
+++ b/drivers/gpu/drm/drm_displayid_internal.h
@@ -97,6 +97,7 @@ struct displayid_header {
 	u8 ext_count;
 } __packed;
 
+#define DISPLAYID_BLOCK_REV	GENMASK(2, 0)
 struct displayid_block {
 	u8 tag;
 	u8 rev;
@@ -125,6 +126,7 @@ struct displayid_detailed_timings_1 {
 	__le16 vsw;
 } __packed;
 
+#define DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT	BIT(3)
 struct displayid_detailed_timing_block {
 	struct displayid_block base;
 	struct displayid_detailed_timings_1 timings[];
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 348aa31aea1b..72a94b1713e2 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -6792,8 +6792,8 @@ static void update_display_info(struct drm_connector *connector,
 }
 
 static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *dev,
-							    const struct displayid_detailed_timings_1 *timings,
-							    bool type_7)
+							    const struct displayid_block *block,
+							    const struct displayid_detailed_timings_1 *timings)
 {
 	struct drm_display_mode *mode;
 	unsigned int pixel_clock = (timings->pixel_clock[0] |
@@ -6809,11 +6809,16 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d
 	unsigned int vsync_width = le16_to_cpu(timings->vsw) + 1;
 	bool hsync_positive = le16_to_cpu(timings->hsync) & (1 << 15);
 	bool vsync_positive = le16_to_cpu(timings->vsync) & (1 << 15);
+	bool type_7 = block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING;
 
 	mode = drm_mode_create(dev);
 	if (!mode)
 		return NULL;
 
+	if (type_7 && FIELD_GET(DISPLAYID_BLOCK_REV, block->rev) >= 1)
+		mode->dsc_passthrough_timings_support =
+			!!(block->rev & DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT);
+
 	/* resolution is kHz for type VII, and 10 kHz for type I */
 	mode->clock = type_7 ? pixel_clock : pixel_clock * 10;
 	mode->hdisplay = hactive;
@@ -6846,7 +6851,6 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
 	int num_timings;
 	struct drm_display_mode *newmode;
 	int num_modes = 0;
-	bool type_7 = block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING;
 	/* blocks must be multiple of 20 bytes length */
 	if (block->num_bytes % 20)
 		return 0;
@@ -6855,7 +6859,7 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
 	for (i = 0; i < num_timings; i++) {
 		struct displayid_detailed_timings_1 *timings = &det->timings[i];
 
-		newmode = drm_mode_displayid_detailed(connector->dev, timings, type_7);
+		newmode = drm_mode_displayid_detailed(connector->dev, block, timings);
 		if (!newmode)
 			continue;
 
diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
index b9bb92e4b029..312e5c03af9a 100644
--- a/include/drm/drm_modes.h
+++ b/include/drm/drm_modes.h
@@ -417,6 +417,16 @@ struct drm_display_mode {
 	 */
 	enum hdmi_picture_aspect picture_aspect_ratio;
 
+	/**
+	 * @dsc_passthrough_timing_support:
+	 *
+	 * Indicates whether this mode timing descriptor is supported
+	 * with specific target DSC bits per pixel only.
+	 *
+	 * VESA vendor-specific data block shall exist with the relevant
+	 * DSC bits per pixel declaration when this flag is set to true.
+	 */
+	bool dsc_passthrough_timings_support;
 };
 
 /**
-- 
2.51.2
Re: [PATCH v6 4/7] drm/edid: parse DSC DPP passthru support flag for mode VII timings
Posted by Jani Nikula 5 days, 9 hours ago 
On Wed, 26 Nov 2025, Yaroslav Bolyukin <iam@lach.pw> wrote:

The commit message goes here.

> Signed-off-by: Yaroslav Bolyukin <iam@lach.pw>
> ---
>  drivers/gpu/drm/drm_displayid_internal.h |  2 ++
>  drivers/gpu/drm/drm_edid.c               | 12 ++++++++----
>  include/drm/drm_modes.h                  | 10 ++++++++++
>  3 files changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm_displayid_internal.h
> index 72f107ae832f..724174b429f2 100644
> --- a/drivers/gpu/drm/drm_displayid_internal.h
> +++ b/drivers/gpu/drm/drm_displayid_internal.h
> @@ -97,6 +97,7 @@ struct displayid_header {
>  	u8 ext_count;
>  } __packed;
>  
> +#define DISPLAYID_BLOCK_REV	GENMASK(2, 0)
>  struct displayid_block {
>  	u8 tag;
>  	u8 rev;
> @@ -125,6 +126,7 @@ struct displayid_detailed_timings_1 {
>  	__le16 vsw;
>  } __packed;
>  
> +#define DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT	BIT(3)
>  struct displayid_detailed_timing_block {
>  	struct displayid_block base;
>  	struct displayid_detailed_timings_1 timings[];
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 348aa31aea1b..72a94b1713e2 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -6792,8 +6792,8 @@ static void update_display_info(struct drm_connector *connector,
>  }
>  
>  static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *dev,
> -							    const struct displayid_detailed_timings_1 *timings,
> -							    bool type_7)
> +							    const struct displayid_block *block,
> +							    const struct displayid_detailed_timings_1 *timings)
>  {
>  	struct drm_display_mode *mode;
>  	unsigned int pixel_clock = (timings->pixel_clock[0] |
> @@ -6809,11 +6809,16 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d
>  	unsigned int vsync_width = le16_to_cpu(timings->vsw) + 1;
>  	bool hsync_positive = le16_to_cpu(timings->hsync) & (1 << 15);
>  	bool vsync_positive = le16_to_cpu(timings->vsync) & (1 << 15);
> +	bool type_7 = block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING;
>  
>  	mode = drm_mode_create(dev);
>  	if (!mode)
>  		return NULL;
>  
> +	if (type_7 && FIELD_GET(DISPLAYID_BLOCK_REV, block->rev) >= 1)
> +		mode->dsc_passthrough_timings_support =
> +			!!(block->rev & DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT);

The !! and parentheses are superfluous.

> +
>  	/* resolution is kHz for type VII, and 10 kHz for type I */
>  	mode->clock = type_7 ? pixel_clock : pixel_clock * 10;
>  	mode->hdisplay = hactive;
> @@ -6846,7 +6851,6 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
>  	int num_timings;
>  	struct drm_display_mode *newmode;
>  	int num_modes = 0;
> -	bool type_7 = block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING;
>  	/* blocks must be multiple of 20 bytes length */
>  	if (block->num_bytes % 20)
>  		return 0;
> @@ -6855,7 +6859,7 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
>  	for (i = 0; i < num_timings; i++) {
>  		struct displayid_detailed_timings_1 *timings = &det->timings[i];
>  
> -		newmode = drm_mode_displayid_detailed(connector->dev, timings, type_7);
> +		newmode = drm_mode_displayid_detailed(connector->dev, block, timings);
>  		if (!newmode)
>  			continue;
>  
> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> index b9bb92e4b029..312e5c03af9a 100644
> --- a/include/drm/drm_modes.h
> +++ b/include/drm/drm_modes.h
> @@ -417,6 +417,16 @@ struct drm_display_mode {
>  	 */
>  	enum hdmi_picture_aspect picture_aspect_ratio;
>  
> +	/**
> +	 * @dsc_passthrough_timing_support:
> +	 *
> +	 * Indicates whether this mode timing descriptor is supported
> +	 * with specific target DSC bits per pixel only.
> +	 *
> +	 * VESA vendor-specific data block shall exist with the relevant
> +	 * DSC bits per pixel declaration when this flag is set to true.
> +	 */
> +	bool dsc_passthrough_timings_support;
>  };
>  
>  /**

-- 
Jani Nikula, Intel
Re: [PATCH v6 4/7] drm/edid: parse DSC DPP passthru support flag for mode VII timings
Posted by Yaroslav 5 days, 8 hours ago 

On 2025-11-26 15:19, Jani Nikula wrote:
> On Wed, 26 Nov 2025, Yaroslav Bolyukin <iam@lach.pw> wrote:
> 
> The commit message goes here.
> 
>> Signed-off-by: Yaroslav Bolyukin <iam@lach.pw>
>> ---
>>   drivers/gpu/drm/drm_displayid_internal.h |  2 ++
>>   drivers/gpu/drm/drm_edid.c               | 12 ++++++++----
>>   include/drm/drm_modes.h                  | 10 ++++++++++
>>   3 files changed, 20 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm_displayid_internal.h
>> index 72f107ae832f..724174b429f2 100644
>> --- a/drivers/gpu/drm/drm_displayid_internal.h
>> +++ b/drivers/gpu/drm/drm_displayid_internal.h
>> @@ -97,6 +97,7 @@ struct displayid_header {
>>   	u8 ext_count;
>>   } __packed;
>>   
>> +#define DISPLAYID_BLOCK_REV	GENMASK(2, 0)
>>   struct displayid_block {
>>   	u8 tag;
>>   	u8 rev;
>> @@ -125,6 +126,7 @@ struct displayid_detailed_timings_1 {
>>   	__le16 vsw;
>>   } __packed;
>>   
>> +#define DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT	BIT(3)
>>   struct displayid_detailed_timing_block {
>>   	struct displayid_block base;
>>   	struct displayid_detailed_timings_1 timings[];
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index 348aa31aea1b..72a94b1713e2 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -6792,8 +6792,8 @@ static void update_display_info(struct drm_connector *connector,
>>   }
>>   
>>   static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *dev,
>> -							    const struct displayid_detailed_timings_1 *timings,
>> -							    bool type_7)
>> +							    const struct displayid_block *block,
>> +							    const struct displayid_detailed_timings_1 *timings)
>>   {
>>   	struct drm_display_mode *mode;
>>   	unsigned int pixel_clock = (timings->pixel_clock[0] |
>> @@ -6809,11 +6809,16 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d
>>   	unsigned int vsync_width = le16_to_cpu(timings->vsw) + 1;
>>   	bool hsync_positive = le16_to_cpu(timings->hsync) & (1 << 15);
>>   	bool vsync_positive = le16_to_cpu(timings->vsync) & (1 << 15);
>> +	bool type_7 = block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING;
>>   
>>   	mode = drm_mode_create(dev);
>>   	if (!mode)
>>   		return NULL;
>>   
>> +	if (type_7 && FIELD_GET(DISPLAYID_BLOCK_REV, block->rev) >= 1)
>> +		mode->dsc_passthrough_timings_support =
>> +			!!(block->rev & DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT);
> 
> The !! and parentheses are superfluous.
> 

Most of the other instances of bitflag parsing logic in kernel seem to 
cast integers to booleans explicitly this way.

I'm fine with simplifying that, I was only doing what everyone else does.

>> +
>>   	/* resolution is kHz for type VII, and 10 kHz for type I */
>>   	mode->clock = type_7 ? pixel_clock : pixel_clock * 10;
>>   	mode->hdisplay = hactive;
>> @@ -6846,7 +6851,6 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
>>   	int num_timings;
>>   	struct drm_display_mode *newmode;
>>   	int num_modes = 0;
>> -	bool type_7 = block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING;
>>   	/* blocks must be multiple of 20 bytes length */
>>   	if (block->num_bytes % 20)
>>   		return 0;
>> @@ -6855,7 +6859,7 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
>>   	for (i = 0; i < num_timings; i++) {
>>   		struct displayid_detailed_timings_1 *timings = &det->timings[i];
>>   
>> -		newmode = drm_mode_displayid_detailed(connector->dev, timings, type_7);
>> +		newmode = drm_mode_displayid_detailed(connector->dev, block, timings);
>>   		if (!newmode)
>>   			continue;
>>   
>> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
>> index b9bb92e4b029..312e5c03af9a 100644
>> --- a/include/drm/drm_modes.h
>> +++ b/include/drm/drm_modes.h
>> @@ -417,6 +417,16 @@ struct drm_display_mode {
>>   	 */
>>   	enum hdmi_picture_aspect picture_aspect_ratio;
>>   
>> +	/**
>> +	 * @dsc_passthrough_timing_support:
>> +	 *
>> +	 * Indicates whether this mode timing descriptor is supported
>> +	 * with specific target DSC bits per pixel only.
>> +	 *
>> +	 * VESA vendor-specific data block shall exist with the relevant
>> +	 * DSC bits per pixel declaration when this flag is set to true.
>> +	 */
>> +	bool dsc_passthrough_timings_support;
>>   };
>>   
>>   /**
>
Re: [PATCH v6 4/7] drm/edid: parse DSC DPP passthru support flag for mode VII timings
Posted by Jani Nikula 5 days, 8 hours ago 
On Wed, 26 Nov 2025, Yaroslav <iam@0la.ch> wrote:
> On 2025-11-26 15:19, Jani Nikula wrote:
>> On Wed, 26 Nov 2025, Yaroslav Bolyukin <iam@lach.pw> wrote:
>>> +	if (type_7 && FIELD_GET(DISPLAYID_BLOCK_REV, block->rev) >= 1)
>>> +		mode->dsc_passthrough_timings_support =
>>> +			!!(block->rev & DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT);
>> 
>> The !! and parentheses are superfluous.
>> 
>
> Most of the other instances of bitflag parsing logic in kernel seem to 
> cast integers to booleans explicitly this way.
>
> I'm fine with simplifying that, I was only doing what everyone else does.

I get that, but such habits originate from the days before std bool. !!
normalizes ints to 0 and 1, but assigning to bool does the same for you.

BR,
Jani.


-- 
Jani Nikula, Intel

Patchew 2.1-devel-b67e4c2

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