| Message ID | 20230109205721.60694-1-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ACPI: Fix selecting the wrong ACPI fwnode for the iGPU on some Dell laptops | expand |
p.s. This fixes a regression in 6.1, adding the regressions list to the Cc. Once we figure out the best way to fix this (this patch is more of a proposal how to fix this rather then a definitive fix), we should also backport the fix to 6.1.y. On 1/9/23 21:57, Hans de Goede wrote: > The Dell Latitude E6430 both with and without the optional NVidia dGPU > has a bug in its ACPI tables which is causing Linux to assign the wrong > ACPI fwnode / companion to the pci_device for the i915 iGPU. > > Specifically under the PCI root bridge there are these 2 ACPI Device()s : > > Scope (_SB.PCI0) > { > Device (GFX0) > { > Name (_ADR, 0x00020000) // _ADR: Address > } > > ... > > Device (VID) > { > Name (_ADR, 0x00020000) // _ADR: Address > ... > > Method (_DOS, 1, NotSerialized) // _DOS: Disable Output Switching > { > VDP8 = Arg0 > VDP1 (One, VDP8) > } > > Method (_DOD, 0, NotSerialized) // _DOD: Display Output Devices > { > ... > } > ... > } > } > > The non-functional GFX0 ACPI device is a problem, because this gets > returned as ACPI companion-device by acpi_find_child_device() for the iGPU. > > This is a long standing problem and the i915 driver does use the ACPI > companion for some things, but works fine without it. > > However since commit 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()") > acpi_get_pci_dev() relies on the physical-node pointer in the acpi_device > and that is set on the wrong acpi_device because of the wrong > acpi_find_child_device() return. This breaks the ACPI video code, leading > to non working backlight control in some cases. > > Make find_child_checks() return a higher score for children which have > pnp-ids set by various scan helpers like acpi_is_video_device(), so > that it picks the right companion-device. > > An alternative approach would be to directly call acpi_is_video_device() > from find_child_checks() but that would be somewhat computationally > expensive given that acpi_find_child_device() iterates over all the > PCI0 children every time it is called. > > Fixes: 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()") > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > drivers/acpi/glue.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c > index 204fe94c7e45..2055dfd7678b 100644 > --- a/drivers/acpi/glue.c > +++ b/drivers/acpi/glue.c > @@ -75,7 +75,7 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev) > } > > #define FIND_CHILD_MIN_SCORE 1 > -#define FIND_CHILD_MAX_SCORE 2 > +#define FIND_CHILD_MAX_SCORE 3 > > static int match_any(struct acpi_device *adev, void *not_used) > { > @@ -89,15 +89,25 @@ static bool acpi_dev_has_children(struct acpi_device *adev) > > static int find_child_checks(struct acpi_device *adev, bool check_children) > { > + int score = FIND_CHILD_MIN_SCORE; > unsigned long long sta; > acpi_status status; > > if (check_children && !acpi_dev_has_children(adev)) > return -ENODEV; > > + /* > + * For devices without a _STA method, prefer devices without a _HID > + * (which conflicts with having an _ADR) but which have been matched > + * in some other way, like e.g. by acpi_is_video_device() over devices > + * with no ids at all. > + */ > + if (!adev->pnp.type.platform_id && adev->pnp.type.hardware_id) > + score++; > + > status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta); > if (status == AE_NOT_FOUND) > - return FIND_CHILD_MIN_SCORE; > + return score; > > if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED)) > return -ENODEV;
On Monday, January 9, 2023 9:57:21 PM CET Hans de Goede wrote: > The Dell Latitude E6430 both with and without the optional NVidia dGPU > has a bug in its ACPI tables which is causing Linux to assign the wrong > ACPI fwnode / companion to the pci_device for the i915 iGPU. > > Specifically under the PCI root bridge there are these 2 ACPI Device()s : > > Scope (_SB.PCI0) > { > Device (GFX0) > { > Name (_ADR, 0x00020000) // _ADR: Address > } > > ... > > Device (VID) > { > Name (_ADR, 0x00020000) // _ADR: Address > ... > > Method (_DOS, 1, NotSerialized) // _DOS: Disable Output Switching > { > VDP8 = Arg0 > VDP1 (One, VDP8) > } > > Method (_DOD, 0, NotSerialized) // _DOD: Display Output Devices > { > ... > } > ... > } > } > > The non-functional GFX0 ACPI device is a problem, because this gets > returned as ACPI companion-device by acpi_find_child_device() for the iGPU. > > This is a long standing problem and the i915 driver does use the ACPI > companion for some things, but works fine without it. > > However since commit 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()") > acpi_get_pci_dev() relies on the physical-node pointer in the acpi_device > and that is set on the wrong acpi_device because of the wrong > acpi_find_child_device() return. This breaks the ACPI video code, leading > to non working backlight control in some cases. Interesting. Sorry for the trouble. > Make find_child_checks() return a higher score for children which have > pnp-ids set by various scan helpers like acpi_is_video_device(), so > that it picks the right companion-device. This has a potential of changing the behavior in some cases that are not relevant here which is generally risky. > An alternative approach would be to directly call acpi_is_video_device() > from find_child_checks() but that would be somewhat computationally > expensive given that acpi_find_child_device() iterates over all the > PCI0 children every time it is called. I agree with the above, but my fix would be something like the patch below (not really tested, but it builds). --- drivers/acpi/glue.c | 14 ++++++++++++-- drivers/acpi/scan.c | 7 +++++-- include/acpi/acpi_bus.h | 3 ++- 3 files changed, 19 insertions(+), 5 deletions(-) Index: linux-pm/include/acpi/acpi_bus.h =================================================================== --- linux-pm.orig/include/acpi/acpi_bus.h +++ linux-pm/include/acpi/acpi_bus.h @@ -230,7 +230,8 @@ struct acpi_pnp_type { u32 hardware_id:1; u32 bus_address:1; u32 platform_id:1; - u32 reserved:29; + u32 backlight:1; + u32 reserved:28; }; struct acpi_device_pnp { Index: linux-pm/drivers/acpi/scan.c =================================================================== --- linux-pm.orig/drivers/acpi/scan.c +++ linux-pm/drivers/acpi/scan.c @@ -1370,9 +1370,12 @@ static void acpi_set_pnp_ids(acpi_handle * Some devices don't reliably have _HIDs & _CIDs, so add * synthetic HIDs to make sure drivers can find them. */ - if (acpi_is_video_device(handle)) + if (acpi_is_video_device(handle)) { acpi_add_id(pnp, ACPI_VIDEO_HID); - else if (acpi_bay_match(handle)) + pnp->type.backlight = 1; + break; + } + if (acpi_bay_match(handle)) acpi_add_id(pnp, ACPI_BAY_HID); else if (acpi_dock_match(handle)) acpi_add_id(pnp, ACPI_DOCK_HID); Index: linux-pm/drivers/acpi/glue.c =================================================================== --- linux-pm.orig/drivers/acpi/glue.c +++ linux-pm/drivers/acpi/glue.c @@ -75,7 +75,8 @@ static struct acpi_bus_type *acpi_get_bu } #define FIND_CHILD_MIN_SCORE 1 -#define FIND_CHILD_MAX_SCORE 2 +#define FIND_CHILD_MID_SCORE 2 +#define FIND_CHILD_MAX_SCORE 3 static int match_any(struct acpi_device *adev, void *not_used) { @@ -96,8 +97,17 @@ static int find_child_checks(struct acpi return -ENODEV; status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta); - if (status == AE_NOT_FOUND) + if (status == AE_NOT_FOUND) { + /* + * Special case: backlight device objects without _STA are + * preferred to other objects with the same _ADR value, because + * it is more likely that they are actually useful. + */ + if (adev->pnp.type.backlight) + return FIND_CHILD_MID_SCORE; + return FIND_CHILD_MIN_SCORE; + } if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED)) return -ENODEV;
Hi Rafael, On 1/10/23 14:33, Rafael J. Wysocki wrote: > On Monday, January 9, 2023 9:57:21 PM CET Hans de Goede wrote: >> The Dell Latitude E6430 both with and without the optional NVidia dGPU >> has a bug in its ACPI tables which is causing Linux to assign the wrong >> ACPI fwnode / companion to the pci_device for the i915 iGPU. >> >> Specifically under the PCI root bridge there are these 2 ACPI Device()s : >> >> Scope (_SB.PCI0) >> { >> Device (GFX0) >> { >> Name (_ADR, 0x00020000) // _ADR: Address >> } >> >> ... >> >> Device (VID) >> { >> Name (_ADR, 0x00020000) // _ADR: Address >> ... >> >> Method (_DOS, 1, NotSerialized) // _DOS: Disable Output Switching >> { >> VDP8 = Arg0 >> VDP1 (One, VDP8) >> } >> >> Method (_DOD, 0, NotSerialized) // _DOD: Display Output Devices >> { >> ... >> } >> ... >> } >> } >> >> The non-functional GFX0 ACPI device is a problem, because this gets >> returned as ACPI companion-device by acpi_find_child_device() for the iGPU. >> >> This is a long standing problem and the i915 driver does use the ACPI >> companion for some things, but works fine without it. >> >> However since commit 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()") >> acpi_get_pci_dev() relies on the physical-node pointer in the acpi_device >> and that is set on the wrong acpi_device because of the wrong >> acpi_find_child_device() return. This breaks the ACPI video code, leading >> to non working backlight control in some cases. > > Interesting. Sorry for the trouble. No problem, as mentioned this is actually a long standing issue / bug in the ACPI tables, it just never surfaced before. >> Make find_child_checks() return a higher score for children which have >> pnp-ids set by various scan helpers like acpi_is_video_device(), so >> that it picks the right companion-device. > > This has a potential of changing the behavior in some cases that are not > relevant here which is generally risky. > >> An alternative approach would be to directly call acpi_is_video_device() >> from find_child_checks() but that would be somewhat computationally >> expensive given that acpi_find_child_device() iterates over all the >> PCI0 children every time it is called. > > I agree with the above, but my fix would be something like the patch below (not > really tested, but it builds). Thanks, I have just given this a spin on my E6430 and I can confirm it still fixes things. I'll send out this version (re-using most of the v1 commitmsg) as a v2 right away. Regards, Hans > > --- > drivers/acpi/glue.c | 14 ++++++++++++-- > drivers/acpi/scan.c | 7 +++++-- > include/acpi/acpi_bus.h | 3 ++- > 3 files changed, 19 insertions(+), 5 deletions(-) > > Index: linux-pm/include/acpi/acpi_bus.h > =================================================================== > --- linux-pm.orig/include/acpi/acpi_bus.h > +++ linux-pm/include/acpi/acpi_bus.h > @@ -230,7 +230,8 @@ struct acpi_pnp_type { > u32 hardware_id:1; > u32 bus_address:1; > u32 platform_id:1; > - u32 reserved:29; > + u32 backlight:1; > + u32 reserved:28; > }; > > struct acpi_device_pnp { > Index: linux-pm/drivers/acpi/scan.c > =================================================================== > --- linux-pm.orig/drivers/acpi/scan.c > +++ linux-pm/drivers/acpi/scan.c > @@ -1370,9 +1370,12 @@ static void acpi_set_pnp_ids(acpi_handle > * Some devices don't reliably have _HIDs & _CIDs, so add > * synthetic HIDs to make sure drivers can find them. > */ > - if (acpi_is_video_device(handle)) > + if (acpi_is_video_device(handle)) { > acpi_add_id(pnp, ACPI_VIDEO_HID); > - else if (acpi_bay_match(handle)) > + pnp->type.backlight = 1; > + break; > + } > + if (acpi_bay_match(handle)) > acpi_add_id(pnp, ACPI_BAY_HID); > else if (acpi_dock_match(handle)) > acpi_add_id(pnp, ACPI_DOCK_HID); > Index: linux-pm/drivers/acpi/glue.c > =================================================================== > --- linux-pm.orig/drivers/acpi/glue.c > +++ linux-pm/drivers/acpi/glue.c > @@ -75,7 +75,8 @@ static struct acpi_bus_type *acpi_get_bu > } > > #define FIND_CHILD_MIN_SCORE 1 > -#define FIND_CHILD_MAX_SCORE 2 > +#define FIND_CHILD_MID_SCORE 2 > +#define FIND_CHILD_MAX_SCORE 3 > > static int match_any(struct acpi_device *adev, void *not_used) > { > @@ -96,8 +97,17 @@ static int find_child_checks(struct acpi > return -ENODEV; > > status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta); > - if (status == AE_NOT_FOUND) > + if (status == AE_NOT_FOUND) { > + /* > + * Special case: backlight device objects without _STA are > + * preferred to other objects with the same _ADR value, because > + * it is more likely that they are actually useful. > + */ > + if (adev->pnp.type.backlight) > + return FIND_CHILD_MID_SCORE; > + > return FIND_CHILD_MIN_SCORE; > + } > > if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED)) > return -ENODEV; > > >
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c index 204fe94c7e45..2055dfd7678b 100644 --- a/drivers/acpi/glue.c +++ b/drivers/acpi/glue.c @@ -75,7 +75,7 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev) } #define FIND_CHILD_MIN_SCORE 1 -#define FIND_CHILD_MAX_SCORE 2 +#define FIND_CHILD_MAX_SCORE 3 static int match_any(struct acpi_device *adev, void *not_used) { @@ -89,15 +89,25 @@ static bool acpi_dev_has_children(struct acpi_device *adev) static int find_child_checks(struct acpi_device *adev, bool check_children) { + int score = FIND_CHILD_MIN_SCORE; unsigned long long sta; acpi_status status; if (check_children && !acpi_dev_has_children(adev)) return -ENODEV; + /* + * For devices without a _STA method, prefer devices without a _HID + * (which conflicts with having an _ADR) but which have been matched + * in some other way, like e.g. by acpi_is_video_device() over devices + * with no ids at all. + */ + if (!adev->pnp.type.platform_id && adev->pnp.type.hardware_id) + score++; + status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta); if (status == AE_NOT_FOUND) - return FIND_CHILD_MIN_SCORE; + return score; if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED)) return -ENODEV;
The Dell Latitude E6430 both with and without the optional NVidia dGPU has a bug in its ACPI tables which is causing Linux to assign the wrong ACPI fwnode / companion to the pci_device for the i915 iGPU. Specifically under the PCI root bridge there are these 2 ACPI Device()s : Scope (_SB.PCI0) { Device (GFX0) { Name (_ADR, 0x00020000) // _ADR: Address } ... Device (VID) { Name (_ADR, 0x00020000) // _ADR: Address ... Method (_DOS, 1, NotSerialized) // _DOS: Disable Output Switching { VDP8 = Arg0 VDP1 (One, VDP8) } Method (_DOD, 0, NotSerialized) // _DOD: Display Output Devices { ... } ... } } The non-functional GFX0 ACPI device is a problem, because this gets returned as ACPI companion-device by acpi_find_child_device() for the iGPU. This is a long standing problem and the i915 driver does use the ACPI companion for some things, but works fine without it. However since commit 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()") acpi_get_pci_dev() relies on the physical-node pointer in the acpi_device and that is set on the wrong acpi_device because of the wrong acpi_find_child_device() return. This breaks the ACPI video code, leading to non working backlight control in some cases. Make find_child_checks() return a higher score for children which have pnp-ids set by various scan helpers like acpi_is_video_device(), so that it picks the right companion-device. An alternative approach would be to directly call acpi_is_video_device() from find_child_checks() but that would be somewhat computationally expensive given that acpi_find_child_device() iterates over all the PCI0 children every time it is called. Fixes: 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()") Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/acpi/glue.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)