[v11,07/11] drm: Add helper functions to handle aspect-ratio flag bits

Commit Message

Nautiyal, Ankit K April 20, 2018, 1:31 p.m. UTC

From: Ankit Nautiyal <[e-mail]>

This patch adds helper functions for determining if aspect-ratio is
expected in user-mode and for allowing/disallowing the aspect-ratio,
if its not expected.

Signed-off-by: Ankit Nautiyal <[e-mail]>
---
 drivers/gpu/drm/drm_modes.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_modes.h     |  4 ++++
 2 files changed, 51 insertions(+)

Comments

Ville Syrjälä April 20, 2018, 2:12 p.m. UTC | #1

On Fri, Apr 20, 2018 at 07:01:47PM +0530, Nautiyal, Ankit K wrote:
> From: Ankit Nautiyal <[e-mail]>
> 
> This patch adds helper functions for determining if aspect-ratio is
> expected in user-mode and for allowing/disallowing the aspect-ratio,
> if its not expected.
> 
> Signed-off-by: Ankit Nautiyal <[e-mail]>
> ---
>  drivers/gpu/drm/drm_modes.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_modes.h     |  4 ++++
>  2 files changed, 51 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index c395a24..d6133e8 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -1759,3 +1759,50 @@ bool drm_mode_is_420(const struct drm_display_info *display,
>  		drm_mode_is_420_also(display, mode);
>  }
>  EXPORT_SYMBOL(drm_mode_is_420);
> +
> +/**
> + * drm_mode_aspect_ratio_allowed - checks if the aspect-ratio information
> + * is expected from the user-mode.
> + *
> + * If the user has set aspect-ratio cap, then the flag of the user-mode is
> + * allowed to contain aspect-ratio value.
> + * If the user does not set aspect-ratio cap, then the only value allowed in the
> + * flags bits is aspect-ratio NONE.
> + *
> + * @file_priv: file private structure to get the user capabilities
> + * @umode: drm_mode_modeinfo struct, whose flag carry the aspect ratio
> + * information.
> + *
> + * Returns:
> + * true if the aspect-ratio info is allowed in the user-mode flags.
> + * false, otherwise.
> + */
> +bool
> +drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
> +			      struct drm_mode_modeinfo *umode)
> +{
> +	return file_priv->aspect_ratio_allowed || (umode->flags &
> +		DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;

Odd line split here. Makes this a bit hard to read.
I would split after the ||

> +}
> +EXPORT_SYMBOL(drm_mode_aspect_ratio_allowed);

Do we actually need to export these? I don't think so.

But I might be wrong. It's a bit hard to see with the way
you split this patch with the actual users in a different patch.

> +
> +/**
> + * drm_mode_filter_aspect_ratio_flags - filters the aspect-ratio bits in the
> + * user-mode flags.
> + *
> + * Checks if the aspect-ratio information is allowed. Resets the aspect-ratio
> + * bits in the user-mode flags, if aspect-ratio info is not allowed.
> + *
> + * @file_priv: file private structure to get the user capabilities.
> + * @umode: drm_mode_modeinfo struct, whose flags' aspect-ratio bits needs to
> + * be filtered.
> + *
> + */
> +void
> +drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
> +				   struct drm_mode_modeinfo *umode)
> +{
> +	if (!drm_mode_aspect_ratio_allowed(file_priv, umode))
> +		umode->flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
> +}
> +EXPORT_SYMBOL(drm_mode_filter_aspect_ratio_flags);
> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> index 2f78b7e..e0b060d 100644
> --- a/include/drm/drm_modes.h
> +++ b/include/drm/drm_modes.h
> @@ -461,6 +461,10 @@ bool drm_mode_is_420_also(const struct drm_display_info *display,
>  			  const struct drm_display_mode *mode);
>  bool drm_mode_is_420(const struct drm_display_info *display,
>  		     const struct drm_display_mode *mode);
> +bool drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
> +				   struct drm_mode_modeinfo *umode);
> +void drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
> +					struct drm_mode_modeinfo *umode);
>  
>  struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
>  				      int hdisplay, int vdisplay, int vrefresh,
> -- 
> 2.7.4

Nautiyal, Ankit K April 23, 2018, 5:25 a.m. UTC | #2

On 4/20/2018 7:42 PM, Ville Syrjälä wrote:
> On Fri, Apr 20, 2018 at 07:01:47PM +0530, Nautiyal, Ankit K wrote:
>> From: Ankit Nautiyal <[e-mail]>
>>
>> This patch adds helper functions for determining if aspect-ratio is
>> expected in user-mode and for allowing/disallowing the aspect-ratio,
>> if its not expected.
>>
>> Signed-off-by: Ankit Nautiyal <[e-mail]>
>> ---
>>   drivers/gpu/drm/drm_modes.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
>>   include/drm/drm_modes.h     |  4 ++++
>>   2 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
>> index c395a24..d6133e8 100644
>> --- a/drivers/gpu/drm/drm_modes.c
>> +++ b/drivers/gpu/drm/drm_modes.c
>> @@ -1759,3 +1759,50 @@ bool drm_mode_is_420(const struct drm_display_info *display,
>>   		drm_mode_is_420_also(display, mode);
>>   }
>>   EXPORT_SYMBOL(drm_mode_is_420);
>> +
>> +/**
>> + * drm_mode_aspect_ratio_allowed - checks if the aspect-ratio information
>> + * is expected from the user-mode.
>> + *
>> + * If the user has set aspect-ratio cap, then the flag of the user-mode is
>> + * allowed to contain aspect-ratio value.
>> + * If the user does not set aspect-ratio cap, then the only value allowed in the
>> + * flags bits is aspect-ratio NONE.
>> + *
>> + * @file_priv: file private structure to get the user capabilities
>> + * @umode: drm_mode_modeinfo struct, whose flag carry the aspect ratio
>> + * information.
>> + *
>> + * Returns:
>> + * true if the aspect-ratio info is allowed in the user-mode flags.
>> + * false, otherwise.
>> + */
>> +bool
>> +drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
>> +			      struct drm_mode_modeinfo *umode)
>> +{
>> +	return file_priv->aspect_ratio_allowed || (umode->flags &
>> +		DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
> Odd line split here. Makes this a bit hard to read.
> I would split after the ||

Agreed. I wasn't sure how to let it have better readability and less 
than 80 char length
at the same time. Will fix this.

>
>> +}
>> +EXPORT_SYMBOL(drm_mode_aspect_ratio_allowed);
> Do we actually need to export these? I don't think so.
>
> But I might be wrong. It's a bit hard to see with the way
> you split this patch with the actual users in a different patch.

These helper functions are used in drm_mode_atomic.c, drm_mode_crtc.c, 
and drm_mode_get_connector.c
The patches are split as to have modes-set handling separate and the 
exposing of connector separate.
Do you suggest this patch to be merged with the patch for handling 
aspect-ratio in modeset?

>> +
>> +/**
>> + * drm_mode_filter_aspect_ratio_flags - filters the aspect-ratio bits in the
>> + * user-mode flags.
>> + *
>> + * Checks if the aspect-ratio information is allowed. Resets the aspect-ratio
>> + * bits in the user-mode flags, if aspect-ratio info is not allowed.
>> + *
>> + * @file_priv: file private structure to get the user capabilities.
>> + * @umode: drm_mode_modeinfo struct, whose flags' aspect-ratio bits needs to
>> + * be filtered.
>> + *
>> + */
>> +void
>> +drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
>> +				   struct drm_mode_modeinfo *umode)
>> +{
>> +	if (!drm_mode_aspect_ratio_allowed(file_priv, umode))
>> +		umode->flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
>> +}
>> +EXPORT_SYMBOL(drm_mode_filter_aspect_ratio_flags);
>> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
>> index 2f78b7e..e0b060d 100644
>> --- a/include/drm/drm_modes.h
>> +++ b/include/drm/drm_modes.h
>> @@ -461,6 +461,10 @@ bool drm_mode_is_420_also(const struct drm_display_info *display,
>>   			  const struct drm_display_mode *mode);
>>   bool drm_mode_is_420(const struct drm_display_info *display,
>>   		     const struct drm_display_mode *mode);
>> +bool drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
>> +				   struct drm_mode_modeinfo *umode);
>> +void drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
>> +					struct drm_mode_modeinfo *umode);
>>   
>>   struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
>>   				      int hdisplay, int vdisplay, int vrefresh,
>> -- 
>> 2.7.4

Ville Syrjälä April 23, 2018, 10:13 a.m. UTC | #3

On Mon, Apr 23, 2018 at 10:55:54AM +0530, Nautiyal, Ankit K wrote:
> 
> 
> On 4/20/2018 7:42 PM, Ville Syrjälä wrote:
> > On Fri, Apr 20, 2018 at 07:01:47PM +0530, Nautiyal, Ankit K wrote:
> >> From: Ankit Nautiyal <[e-mail]>
> >>
> >> This patch adds helper functions for determining if aspect-ratio is
> >> expected in user-mode and for allowing/disallowing the aspect-ratio,
> >> if its not expected.
> >>
> >> Signed-off-by: Ankit Nautiyal <[e-mail]>
> >> ---
> >>   drivers/gpu/drm/drm_modes.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
> >>   include/drm/drm_modes.h     |  4 ++++
> >>   2 files changed, 51 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> >> index c395a24..d6133e8 100644
> >> --- a/drivers/gpu/drm/drm_modes.c
> >> +++ b/drivers/gpu/drm/drm_modes.c
> >> @@ -1759,3 +1759,50 @@ bool drm_mode_is_420(const struct drm_display_info *display,
> >>   		drm_mode_is_420_also(display, mode);
> >>   }
> >>   EXPORT_SYMBOL(drm_mode_is_420);
> >> +
> >> +/**
> >> + * drm_mode_aspect_ratio_allowed - checks if the aspect-ratio information
> >> + * is expected from the user-mode.
> >> + *
> >> + * If the user has set aspect-ratio cap, then the flag of the user-mode is
> >> + * allowed to contain aspect-ratio value.
> >> + * If the user does not set aspect-ratio cap, then the only value allowed in the
> >> + * flags bits is aspect-ratio NONE.
> >> + *
> >> + * @file_priv: file private structure to get the user capabilities
> >> + * @umode: drm_mode_modeinfo struct, whose flag carry the aspect ratio
> >> + * information.
> >> + *
> >> + * Returns:
> >> + * true if the aspect-ratio info is allowed in the user-mode flags.
> >> + * false, otherwise.
> >> + */
> >> +bool
> >> +drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
> >> +			      struct drm_mode_modeinfo *umode)
> >> +{
> >> +	return file_priv->aspect_ratio_allowed || (umode->flags &
> >> +		DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
> > Odd line split here. Makes this a bit hard to read.
> > I would split after the ||
> 
> Agreed. I wasn't sure how to let it have better readability and less 
> than 80 char length
> at the same time. Will fix this.
> 
> >
> >> +}
> >> +EXPORT_SYMBOL(drm_mode_aspect_ratio_allowed);
> > Do we actually need to export these? I don't think so.
> >
> > But I might be wrong. It's a bit hard to see with the way
> > you split this patch with the actual users in a different patch.
> 
> These helper functions are used in drm_mode_atomic.c, drm_mode_crtc.c, 
> and drm_mode_get_connector.c
> The patches are split as to have modes-set handling separate and the 
> exposing of connector separate.
> Do you suggest this patch to be merged with the patch for handling 
> aspect-ratio in modeset?

Usually if you add a function you should do it in the same patch where
you add the user(s) for said function. Otherwise it's impossibly to
judge whether the new function is any good.

> 
> >> +
> >> +/**
> >> + * drm_mode_filter_aspect_ratio_flags - filters the aspect-ratio bits in the
> >> + * user-mode flags.
> >> + *
> >> + * Checks if the aspect-ratio information is allowed. Resets the aspect-ratio
> >> + * bits in the user-mode flags, if aspect-ratio info is not allowed.
> >> + *
> >> + * @file_priv: file private structure to get the user capabilities.
> >> + * @umode: drm_mode_modeinfo struct, whose flags' aspect-ratio bits needs to
> >> + * be filtered.
> >> + *
> >> + */
> >> +void
> >> +drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
> >> +				   struct drm_mode_modeinfo *umode)
> >> +{
> >> +	if (!drm_mode_aspect_ratio_allowed(file_priv, umode))
> >> +		umode->flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
> >> +}
> >> +EXPORT_SYMBOL(drm_mode_filter_aspect_ratio_flags);
> >> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> >> index 2f78b7e..e0b060d 100644
> >> --- a/include/drm/drm_modes.h
> >> +++ b/include/drm/drm_modes.h
> >> @@ -461,6 +461,10 @@ bool drm_mode_is_420_also(const struct drm_display_info *display,
> >>   			  const struct drm_display_mode *mode);
> >>   bool drm_mode_is_420(const struct drm_display_info *display,
> >>   		     const struct drm_display_mode *mode);
> >> +bool drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
> >> +				   struct drm_mode_modeinfo *umode);
> >> +void drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
> >> +					struct drm_mode_modeinfo *umode);
> >>   
> >>   struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
> >>   				      int hdisplay, int vdisplay, int vrefresh,
> >> -- 
> >> 2.7.4
>

Jani Nikula April 23, 2018, 10:22 a.m. UTC | #4

On Mon, 23 Apr 2018, "Nautiyal, Ankit K" <[e-mail]> wrote:
> On 4/20/2018 7:42 PM, Ville Syrjälä wrote:
>> On Fri, Apr 20, 2018 at 07:01:47PM +0530, Nautiyal, Ankit K wrote:
>>> From: Ankit Nautiyal <[e-mail]>
>>> +bool
>>> +drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
>>> +			      struct drm_mode_modeinfo *umode)
>>> +{
>>> +	return file_priv->aspect_ratio_allowed || (umode->flags &
>>> +		DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
>> Odd line split here. Makes this a bit hard to read.
>> I would split after the ||
>
> Agreed. I wasn't sure how to let it have better readability and less
> than 80 char length at the same time. Will fix this.

80 chars is not a strict requirement. Readability is. ;)

BR,
Jani.

Nautiyal, Ankit K April 24, 2018, 4:01 a.m. UTC | #5

On 4/23/2018 3:52 PM, Jani Nikula wrote:
> On Mon, 23 Apr 2018, "Nautiyal, Ankit K" <[e-mail]> wrote:
>> On 4/20/2018 7:42 PM, Ville Syrjälä wrote:
>>> On Fri, Apr 20, 2018 at 07:01:47PM +0530, Nautiyal, Ankit K wrote:
>>>> From: Ankit Nautiyal <[e-mail]>
>>>> +bool
>>>> +drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
>>>> +			      struct drm_mode_modeinfo *umode)
>>>> +{
>>>> +	return file_priv->aspect_ratio_allowed || (umode->flags &
>>>> +		DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
>>> Odd line split here. Makes this a bit hard to read.
>>> I would split after the ||
>> Agreed. I wasn't sure how to let it have better readability and less
>> than 80 char length at the same time. Will fix this.
> 80 chars is not a strict requirement. Readability is. ;)
>
> BR,
> Jani.

Roger that! :)

Nautiyal, Ankit K April 24, 2018, 4:10 a.m. UTC | #6

On 4/23/2018 3:43 PM, Ville Syrjälä wrote:
> On Mon, Apr 23, 2018 at 10:55:54AM +0530, Nautiyal, Ankit K wrote:
>>
>> On 4/20/2018 7:42 PM, Ville Syrjälä wrote:
>>> On Fri, Apr 20, 2018 at 07:01:47PM +0530, Nautiyal, Ankit K wrote:
>>>> From: Ankit Nautiyal <[e-mail]>
>>>>
>>>> This patch adds helper functions for determining if aspect-ratio is
>>>> expected in user-mode and for allowing/disallowing the aspect-ratio,
>>>> if its not expected.
>>>>
>>>> Signed-off-by: Ankit Nautiyal <[e-mail]>
>>>> ---
>>>>    drivers/gpu/drm/drm_modes.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
>>>>    include/drm/drm_modes.h     |  4 ++++
>>>>    2 files changed, 51 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
>>>> index c395a24..d6133e8 100644
>>>> --- a/drivers/gpu/drm/drm_modes.c
>>>> +++ b/drivers/gpu/drm/drm_modes.c
>>>> @@ -1759,3 +1759,50 @@ bool drm_mode_is_420(const struct drm_display_info *display,
>>>>             drm_mode_is_420_also(display, mode);
>>>>    }
>>>>    EXPORT_SYMBOL(drm_mode_is_420);
>>>> +
>>>> +/**
>>>> + * drm_mode_aspect_ratio_allowed - checks if the aspect-ratio information
>>>> + * is expected from the user-mode.
>>>> + *
>>>> + * If the user has set aspect-ratio cap, then the flag of the user-mode is
>>>> + * allowed to contain aspect-ratio value.
>>>> + * If the user does not set aspect-ratio cap, then the only value allowed in the
>>>> + * flags bits is aspect-ratio NONE.
>>>> + *
>>>> + * @file_priv: file private structure to get the user capabilities
>>>> + * @umode: drm_mode_modeinfo struct, whose flag carry the aspect ratio
>>>> + * information.
>>>> + *
>>>> + * Returns:
>>>> + * true if the aspect-ratio info is allowed in the user-mode flags.
>>>> + * false, otherwise.
>>>> + */
>>>> +bool
>>>> +drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
>>>> +                        struct drm_mode_modeinfo *umode)
>>>> +{
>>>> +  return file_priv->aspect_ratio_allowed || (umode->flags &
>>>> +          DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
>>> Odd line split here. Makes this a bit hard to read.
>>> I would split after the ||
>> Agreed. I wasn't sure how to let it have better readability and less
>> than 80 char length
>> at the same time. Will fix this.
>>
>>>> +}
>>>> +EXPORT_SYMBOL(drm_mode_aspect_ratio_allowed);
>>> Do we actually need to export these? I don't think so.
>>>
>>> But I might be wrong. It's a bit hard to see with the way
>>> you split this patch with the actual users in a different patch.
>> These helper functions are used in drm_mode_atomic.c, drm_mode_crtc.c,
>> and drm_mode_get_connector.c
>> The patches are split as to have modes-set handling separate and the
>> exposing of connector separate.
>> Do you suggest this patch to be merged with the patch for handling
>> aspect-ratio in modeset?
> Usually if you add a function you should do it in the same patch where
> you add the user(s) for said function. Otherwise it's impossibly to
> judge whether the new function is any good.

That makes sense. I will merge this patch with the patch for handling 
aspect ratio in modeset path,
where its actually used.

>
>>>> +
>>>> +/**
>>>> + * drm_mode_filter_aspect_ratio_flags - filters the aspect-ratio bits in the
>>>> + * user-mode flags.
>>>> + *
>>>> + * Checks if the aspect-ratio information is allowed. Resets the aspect-ratio
>>>> + * bits in the user-mode flags, if aspect-ratio info is not allowed.
>>>> + *
>>>> + * @file_priv: file private structure to get the user capabilities.
>>>> + * @umode: drm_mode_modeinfo struct, whose flags' aspect-ratio bits needs to
>>>> + * be filtered.
>>>> + *
>>>> + */
>>>> +void
>>>> +drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
>>>> +                             struct drm_mode_modeinfo *umode)
>>>> +{
>>>> +  if (!drm_mode_aspect_ratio_allowed(file_priv, umode))
>>>> +          umode->flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_mode_filter_aspect_ratio_flags);
>>>> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
>>>> index 2f78b7e..e0b060d 100644
>>>> --- a/include/drm/drm_modes.h
>>>> +++ b/include/drm/drm_modes.h
>>>> @@ -461,6 +461,10 @@ bool drm_mode_is_420_also(const struct drm_display_info *display,
>>>>                       const struct drm_display_mode *mode);
>>>>    bool drm_mode_is_420(const struct drm_display_info *display,
>>>>                  const struct drm_display_mode *mode);
>>>> +bool drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
>>>> +                             struct drm_mode_modeinfo *umode);
>>>> +void drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
>>>> +                                  struct drm_mode_modeinfo *umode);
>>>>
>>>>    struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
>>>>                                   int hdisplay, int vdisplay, int vrefresh,
>>>> --
>>>> 2.7.4
> --
> Ville Syrjälä
> Intel

Patch

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index c395a24..d6133e8 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1759,3 +1759,50 @@  bool drm_mode_is_420(const struct drm_display_info *display,
 		drm_mode_is_420_also(display, mode);
 }
 EXPORT_SYMBOL(drm_mode_is_420);
+
+/**
+ * drm_mode_aspect_ratio_allowed - checks if the aspect-ratio information
+ * is expected from the user-mode.
+ *
+ * If the user has set aspect-ratio cap, then the flag of the user-mode is
+ * allowed to contain aspect-ratio value.
+ * If the user does not set aspect-ratio cap, then the only value allowed in the
+ * flags bits is aspect-ratio NONE.
+ *
+ * @file_priv: file private structure to get the user capabilities
+ * @umode: drm_mode_modeinfo struct, whose flag carry the aspect ratio
+ * information.
+ *
+ * Returns:
+ * true if the aspect-ratio info is allowed in the user-mode flags.
+ * false, otherwise.
+ */
+bool
+drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
+			      struct drm_mode_modeinfo *umode)
+{
+	return file_priv->aspect_ratio_allowed || (umode->flags &
+		DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
+}
+EXPORT_SYMBOL(drm_mode_aspect_ratio_allowed);
+
+/**
+ * drm_mode_filter_aspect_ratio_flags - filters the aspect-ratio bits in the
+ * user-mode flags.
+ *
+ * Checks if the aspect-ratio information is allowed. Resets the aspect-ratio
+ * bits in the user-mode flags, if aspect-ratio info is not allowed.
+ *
+ * @file_priv: file private structure to get the user capabilities.
+ * @umode: drm_mode_modeinfo struct, whose flags' aspect-ratio bits needs to
+ * be filtered.
+ *
+ */
+void
+drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
+				   struct drm_mode_modeinfo *umode)
+{
+	if (!drm_mode_aspect_ratio_allowed(file_priv, umode))
+		umode->flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
+}
+EXPORT_SYMBOL(drm_mode_filter_aspect_ratio_flags);
diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
index 2f78b7e..e0b060d 100644
--- a/include/drm/drm_modes.h
+++ b/include/drm/drm_modes.h
@@ -461,6 +461,10 @@  bool drm_mode_is_420_also(const struct drm_display_info *display,
 			  const struct drm_display_mode *mode);
 bool drm_mode_is_420(const struct drm_display_info *display,
 		     const struct drm_display_mode *mode);
+bool drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
+				   struct drm_mode_modeinfo *umode);
+void drm_mode_filter_aspect_ratio_flags(const struct drm_file *file_priv,
+					struct drm_mode_modeinfo *umode);
 
 struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
 				      int hdisplay, int vdisplay, int vrefresh,