The value of "min_input_signal" returned from ATIF on a Framework AMD 13 is "12". This leads to a fairly bright minimum display backlight.
Introduce a quirk to override "min_input_signal" to "0" which leads to a much lower minimum brightness, which is still readable even in daylight. Tested on a Framework AMD 13 BIOS 3.05 and Framework AMD 16. Link: https://community.frame.work/t/25711/9 Link: https://community.frame.work/t/47036 Signed-off-by: Thomas Weißschuh <li...@weissschuh.net> --- drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 35 ++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c index 7099ff9cf8c5..b481889f7491 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c @@ -25,6 +25,7 @@ #include <linux/pci.h> #include <linux/acpi.h> #include <linux/backlight.h> +#include <linux/dmi.h> #include <linux/slab.h> #include <linux/xarray.h> #include <linux/power_supply.h> @@ -130,6 +131,35 @@ static struct amdgpu_acpi_priv { struct amdgpu_atcs atcs; } amdgpu_acpi_priv; +struct amdgpu_acpi_quirks { + bool ignore_min_input_signal; +}; + +static const struct dmi_system_id amdgpu_acpi_quirk_table[] = { + { + /* the Framework Laptop 13 (AMD Ryzen) and 16 (AMD Ryzen) */ + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Framework"), + DMI_MATCH(DMI_PRODUCT_NAME, "AMD Ryzen"), + DMI_MATCH(DMI_PRODUCT_FAMILY, "Laptop"), + }, + .driver_data = &(struct amdgpu_acpi_quirks) { + .ignore_min_input_signal = true, + }, + }, + {} +}; + +static const struct amdgpu_acpi_quirks *amdgpu_acpi_get_quirks(void) +{ + const struct dmi_system_id *dmi_id; + + dmi_id = dmi_first_match(amdgpu_acpi_quirk_table); + if (!dmi_id) + return NULL; + return dmi_id->driver_data; +} + /* Call the ATIF method */ /** @@ -1388,6 +1418,7 @@ bool amdgpu_acpi_should_gpu_reset(struct amdgpu_device *adev) */ void amdgpu_acpi_detect(void) { + const struct amdgpu_acpi_quirks *quirks = amdgpu_acpi_get_quirks(); struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif; struct amdgpu_atcs *atcs = &amdgpu_acpi_priv.atcs; struct pci_dev *pdev = NULL; @@ -1429,6 +1460,10 @@ void amdgpu_acpi_detect(void) ret); atif->backlight_caps.caps_valid = false; } + if (quirks && quirks->ignore_min_input_signal) { + DRM_INFO("amdgpu_acpi quirk: min_input_signal=0\n"); + atif->backlight_caps.min_input_signal = 0; + } } else { atif->backlight_caps.caps_valid = false; } --- base-commit: 83a7eefedc9b56fe7bfeff13b6c7356688ffa670 change-id: 20240610-amdgpu-min-backlight-quirk-8402fd8e736a Best regards, -- Thomas Weißschuh <li...@weissschuh.net>
