| Message ID | 20240812-amdgpu-min-backlight-quirk-v4-1-56a63ff897b7@weissschuh.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Minimum backlight overrides and implementation for amdgpu | expand |
On Mon, 12 Aug 2024, Thomas Weißschuh <linux@weissschuh.net> wrote: > Panels using a PWM-controlled backlight source without an do not have a > standard way to communicate their valid PWM ranges. > On x86 the ranges are read from ACPI through driver-specific tables. > The built-in ranges are not necessarily correct, or may grow stale if an > older device can be retrofitted with newer panels. > > Add a quirk infrastructure with which the minimum valid backlight value > can be maintained as part of the kernel. > > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> > --- > Documentation/gpu/drm-kms-helpers.rst | 3 ++ > drivers/gpu/drm/Kconfig | 4 ++ > drivers/gpu/drm/Makefile | 1 + > drivers/gpu/drm/drm_panel_backlight_quirks.c | 69 ++++++++++++++++++++++++++++ > include/drm/drm_utils.h | 3 ++ > 5 files changed, 80 insertions(+) > > diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst > index 8435e8621cc0..a26989500129 100644 > --- a/Documentation/gpu/drm-kms-helpers.rst > +++ b/Documentation/gpu/drm-kms-helpers.rst > @@ -230,6 +230,9 @@ Panel Helper Reference > .. kernel-doc:: drivers/gpu/drm/drm_panel_orientation_quirks.c > :export: > > +.. kernel-doc:: drivers/gpu/drm/drm_panel_backlight_quirks.c > + :export: > + > Panel Self Refresh Helper Reference > =================================== > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index 6b2c6b91f962..9ebb8cdb535e 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -454,6 +454,10 @@ config DRM_HYPERV > config DRM_EXPORT_FOR_TESTS > bool > > +# Separate option as not all DRM drivers use it > +config DRM_PANEL_BACKLIGHT_QUIRKS > + tristate > + > config DRM_LIB_RANDOM > bool > default n > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > index 68cc9258ffc4..adf85999aee2 100644 > --- a/drivers/gpu/drm/Makefile > +++ b/drivers/gpu/drm/Makefile > @@ -92,6 +92,7 @@ drm-$(CONFIG_DRM_PANIC) += drm_panic.o > obj-$(CONFIG_DRM) += drm.o > > obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) += drm_panel_orientation_quirks.o > +obj-$(CONFIG_DRM_PANEL_BACKLIGHT_QUIRKS) += drm_panel_backlight_quirks.o > > # > # Memory-management helpers > diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm/drm_panel_backlight_quirks.c > new file mode 100644 > index 000000000000..a88e77db97c5 > --- /dev/null > +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c > @@ -0,0 +1,69 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include <linux/array_size.h> > +#include <linux/dmi.h> > +#include <linux/mod_devicetable.h> > +#include <linux/module.h> > +#include <drm/drm_utils.h> > + > +struct drm_panel_min_backlight_quirk { > + struct { > + enum dmi_field field; > + const char * const value; > + } dmi_match; > + struct drm_edid_ident ident; > + u8 min_brightness; > +}; > + > +static const struct drm_panel_min_backlight_quirk drm_panel_min_backlight_quirks[] = { > +}; > + > +static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel_min_backlight_quirk *quirk, > + const struct drm_edid *edid) > +{ > + if (!dmi_match(quirk->dmi_match.field, quirk->dmi_match.value)) > + return false; > + > + if (!drm_edid_match(edid, &quirk->ident)) > + return false; > + > + return true; > +} > + > +/** > + * drm_get_panel_min_brightness_quirk - Get minimum supported brightness level for a panel. > + * @edid: EDID of the panel to check > + * > + * This function checks for platform specific (e.g. DMI based) quirks > + * providing info on the minimum backlight brightness for systems where this > + * cannot be probed correctly from the hard-/firm-ware. > + * > + * Returns: > + * A negative error value or > + * an override value in the range [0, 255] representing 0-100% to be scaled to > + * the drivers target range. > + */ > +int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid) > +{ > + const struct drm_panel_min_backlight_quirk *quirk; > + size_t i; > + > + if (!IS_ENABLED(CONFIG_DMI)) > + return -ENODATA; > + > + if (!edid) > + return -EINVAL; > + > + for (i = 0; i < ARRAY_SIZE(drm_panel_min_backlight_quirks); i++) { > + quirk = &drm_panel_min_backlight_quirks[i]; > + > + if (drm_panel_min_backlight_quirk_matches(quirk, edid)) > + return quirk->min_brightness; > + } > + > + return -ENODATA; > +} > +EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk); > + > +MODULE_DESCRIPTION("Quirks for panel backlight overrides"); > +MODULE_LICENSE("GPL"); > diff --git a/include/drm/drm_utils.h b/include/drm/drm_utils.h > index 70775748d243..267711028dd4 100644 > --- a/include/drm/drm_utils.h > +++ b/include/drm/drm_utils.h > @@ -11,9 +11,12 @@ > #define __DRM_UTILS_H__ > > #include <linux/types.h> > +#include <drm/drm_edid.h> Please prefer forward declarations over includes where possible. Here, struct drm_edid; is sufficient. BR, Jani. > > int drm_get_panel_orientation_quirk(int width, int height); > > +int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid); > + > signed long drm_timeout_abs_to_jiffies(int64_t timeout_nsec); > > #endif
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst index 8435e8621cc0..a26989500129 100644 --- a/Documentation/gpu/drm-kms-helpers.rst +++ b/Documentation/gpu/drm-kms-helpers.rst @@ -230,6 +230,9 @@ Panel Helper Reference .. kernel-doc:: drivers/gpu/drm/drm_panel_orientation_quirks.c :export: +.. kernel-doc:: drivers/gpu/drm/drm_panel_backlight_quirks.c + :export: + Panel Self Refresh Helper Reference =================================== diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 6b2c6b91f962..9ebb8cdb535e 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -454,6 +454,10 @@ config DRM_HYPERV config DRM_EXPORT_FOR_TESTS bool +# Separate option as not all DRM drivers use it +config DRM_PANEL_BACKLIGHT_QUIRKS + tristate + config DRM_LIB_RANDOM bool default n diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 68cc9258ffc4..adf85999aee2 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -92,6 +92,7 @@ drm-$(CONFIG_DRM_PANIC) += drm_panic.o obj-$(CONFIG_DRM) += drm.o obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) += drm_panel_orientation_quirks.o +obj-$(CONFIG_DRM_PANEL_BACKLIGHT_QUIRKS) += drm_panel_backlight_quirks.o # # Memory-management helpers diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm/drm_panel_backlight_quirks.c new file mode 100644 index 000000000000..a88e77db97c5 --- /dev/null +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c @@ -0,0 +1,69 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/array_size.h> +#include <linux/dmi.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <drm/drm_utils.h> + +struct drm_panel_min_backlight_quirk { + struct { + enum dmi_field field; + const char * const value; + } dmi_match; + struct drm_edid_ident ident; + u8 min_brightness; +}; + +static const struct drm_panel_min_backlight_quirk drm_panel_min_backlight_quirks[] = { +}; + +static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel_min_backlight_quirk *quirk, + const struct drm_edid *edid) +{ + if (!dmi_match(quirk->dmi_match.field, quirk->dmi_match.value)) + return false; + + if (!drm_edid_match(edid, &quirk->ident)) + return false; + + return true; +} + +/** + * drm_get_panel_min_brightness_quirk - Get minimum supported brightness level for a panel. + * @edid: EDID of the panel to check + * + * This function checks for platform specific (e.g. DMI based) quirks + * providing info on the minimum backlight brightness for systems where this + * cannot be probed correctly from the hard-/firm-ware. + * + * Returns: + * A negative error value or + * an override value in the range [0, 255] representing 0-100% to be scaled to + * the drivers target range. + */ +int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid) +{ + const struct drm_panel_min_backlight_quirk *quirk; + size_t i; + + if (!IS_ENABLED(CONFIG_DMI)) + return -ENODATA; + + if (!edid) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(drm_panel_min_backlight_quirks); i++) { + quirk = &drm_panel_min_backlight_quirks[i]; + + if (drm_panel_min_backlight_quirk_matches(quirk, edid)) + return quirk->min_brightness; + } + + return -ENODATA; +} +EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk); + +MODULE_DESCRIPTION("Quirks for panel backlight overrides"); +MODULE_LICENSE("GPL"); diff --git a/include/drm/drm_utils.h b/include/drm/drm_utils.h index 70775748d243..267711028dd4 100644 --- a/include/drm/drm_utils.h +++ b/include/drm/drm_utils.h @@ -11,9 +11,12 @@ #define __DRM_UTILS_H__ #include <linux/types.h> +#include <drm/drm_edid.h> int drm_get_panel_orientation_quirk(int width, int height); +int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid); + signed long drm_timeout_abs_to_jiffies(int64_t timeout_nsec); #endif
Panels using a PWM-controlled backlight source without an do not have a standard way to communicate their valid PWM ranges. On x86 the ranges are read from ACPI through driver-specific tables. The built-in ranges are not necessarily correct, or may grow stale if an older device can be retrofitted with newer panels. Add a quirk infrastructure with which the minimum valid backlight value can be maintained as part of the kernel. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- Documentation/gpu/drm-kms-helpers.rst | 3 ++ drivers/gpu/drm/Kconfig | 4 ++ drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_panel_backlight_quirks.c | 69 ++++++++++++++++++++++++++++ include/drm/drm_utils.h | 3 ++ 5 files changed, 80 insertions(+)