+Kieran
On 6/10/2024 14:26, Thomas Weißschuh wrote:
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 <linux@xxxxxxxxxxxxxx>
---
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"),
+ },
Two problems I see:
1) This really "should" be fixed in the BIOS. I added Kieran to the
thread for comments if that's viable.
2) IMO this is going to match too liberally across all potential
Framework models. If they introduce a refreshed motherboard for either
product then the quirk would apply to both products when we don't know
that such a deficiency would exist.
You can reference drivers/platform/x86/amd/pmc/pmc-quirks.c for what we
used for a quirk that was matching against a single product and single
BIOS.
But FWIW if that issue isn't fixed in the next BIOS I think we'll end up
needing to tear out the BIOS string match and match just the platform.
+ .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,
