Op 21-10-2020 om 08:54 schreef Ken Huang:
> From: Adrian Salido <sali...@google.com>
>
> Some displays may support Low Power modes, however, these modes may
> require special handling as they would usually require lower OPR
> content on framebuffers. Add a drm mode flag to specify display
> capability to support low power mode, and add a drm client cap for
> it. If a client doesn't support the capability, that will filter it
> out for the client.
>
> Signed-off-by: Adrian Salido <sali...@google.com>
> Signed-off-by: Ken Huang <kenbshu...@google.com>
> ---
> drivers/gpu/drm/drm_connector.c | 4 ++++
> drivers/gpu/drm/drm_ioctl.c | 5 +++++
> include/drm/drm_file.h | 7 +++++++
> include/uapi/drm/drm.h | 10 ++++++++++
> include/uapi/drm/drm_mode.h | 3 +++
> 5 files changed, 29 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 717c4e7271b0..46a29b156ffa 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -2318,6 +2318,10 @@ drm_mode_expose_to_userspace(const struct
> drm_display_mode *mode,
> }
> }
>
> + if (!file_priv->low_power_modes_allowed &&
> + (mode->flags & DRM_MODE_FLAG_LOW_POWER))
> + return false;
> +
> return true;
> }
>
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index 789ee65ac1f5..e7e025698b3b 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -362,6 +362,11 @@ drm_setclientcap(struct drm_device *dev, void *data,
> struct drm_file *file_priv)
> return -EINVAL;
> file_priv->writeback_connectors = req->value;
> break;
> + case DRM_CLIENT_CAP_LOW_POWER_MODES:
> + if (req->value > 1)
> + return -EINVAL;
> + file_priv->low_power_modes_allowed = req->value;
> + break;
> default:
> return -EINVAL;
> }
> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> index 716990bace10..2fa66c32f066 100644
> --- a/include/drm/drm_file.h
> +++ b/include/drm/drm_file.h
> @@ -212,6 +212,13 @@ struct drm_file {
> */
> bool was_master;
>
> + /**
> + * @low_power_modes_allowed:
> + *
> + * True if the client understands how to work with low power modes
> + */
> + bool low_power_modes_allowed;
> +
> /**
> * @is_master:
> *
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 808b48a93330..12f39a628bb5 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -698,6 +698,16 @@ struct drm_get_cap {
> */
> #define DRM_CLIENT_CAP_WRITEBACK_CONNECTORS 5
>
> +/**
> + * DRM_CLIENT_CAP_LOW_POWER_MODES
> + *
> + * If set to 1, the DRM core will expose modes that support Lower Power at
> the
> + * potential cost of reduced fidelity. Special care must be taken by clients
> + * that work with these modes, (ex. framebuffer contents are expected to
> + * have reduced OPRs)
> + */
> +#define DRM_CLIENT_CAP_LOW_POWER_MODES 6
> +
> /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
> struct drm_set_client_cap {
> __u64 capability;
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 863eda048265..71137280b1e6 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -124,6 +124,8 @@ extern "C" {
> #define DRM_MODE_FLAG_PIC_AR_256_135 \
> (DRM_MODE_PICTURE_ASPECT_256_135<<19)
>
> +#define DRM_MODE_FLAG_LOW_POWER (1<<23)
> +
> #define DRM_MODE_FLAG_ALL (DRM_MODE_FLAG_PHSYNC | \
> DRM_MODE_FLAG_NHSYNC | \
> DRM_MODE_FLAG_PVSYNC | \
> @@ -136,6 +138,7 @@ extern "C" {
> DRM_MODE_FLAG_HSKEW | \
> DRM_MODE_FLAG_DBLCLK | \
> DRM_MODE_FLAG_CLKDIV2 | \
> + DRM_MODE_FLAG_LOW_POWER | \
> DRM_MODE_FLAG_3D_MASK)
>
> /* DPMS flags */
Hey,
The wording seems to be a bit generic, with just the description I have no idea
how to implement this in userspace, do you have an implementation as well?
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