Hi, On 10/27/21 20:52, Rafael J. Wysocki wrote: > On Mon, Oct 25, 2021 at 11:41 AM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: >> >> The clk and regulator frameworks expect clk/regulator consumer-devices >> to have info about the consumed clks/regulators described in the device's >> fw_node. >> >> To work around cases where this info is not present in the firmware tables, >> which is often the case on x86/ACPI devices, both frameworks allow the >> provider-driver to attach info about consumers to the clks/regulators >> when registering these. >> >> This causes problems with the probe ordering wrt drivers for consumers >> of these clks/regulators. Since the lookups are only registered when the >> provider-driver binds, trying to get these clks/regulators before then >> results in a -ENOENT error for clks and a dummy regulator for regulators. >> >> One case where we hit this issue is camera sensors such as e.g. the OV8865 >> sensor found on the Microsoft Surface Go. The sensor uses clks, regulators >> and GPIOs provided by a TPS68470 PMIC which is described in an INT3472 >> ACPI device. There is special platform code handling this and setting >> platform_data with the necessary consumer info on the MFD cells >> instantiated for the PMIC under: drivers/platform/x86/intel/int3472. >> >> For this to work properly the ov8865 driver must not bind to the I2C-client >> for the OV8865 sensor until after the TPS68470 PMIC gpio, regulator and >> clk MFD cells have all been fully setup. >> >> The OV8865 on the Microsoft Surface Go is just one example, all X86 >> devices using the Intel IPU3 camera block found on recent Intel SoCs >> have similar issues where there is an INT3472 HID ACPI-device, which >> describes the clks and regulators, and the driver for this INT3472 device >> must be fully initialized before the sensor driver (any sensor driver) >> binds for things to work properly. >> >> On these devices the ACPI nodes describing the sensors all have a _DEP >> dependency on the matching INT3472 ACPI device (there is one per sensor). >> >> This allows solving the probe-ordering problem by delaying the enumeration >> (instantiation of the I2C-client in the ov8865 example) of ACPI-devices >> which have a _DEP dependency on an INT3472 device. >> >> The new acpi_dev_ready_for_enumeration() helper used for this is also >> exported because for devices, which have the enumeration_by_parent flag >> set, the parent-driver will do its own scan of child ACPI devices and >> it will try to enumerate those during its probe(). Code doing this such >> as e.g. the i2c-core-acpi.c code must call this new helper to ensure >> that it too delays the enumeration until all the _DEP dependencies are >> met on devices which have the new honor_deps flag set. >> >> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Thanks, note the idea (my idea at least) is for you to pick up patches 1 + 2 as 5.17 material (patch 2 already has an ack from wsa for this). Regards, Hans >> --- >> Changes in v4: >> - Move the acpi_dev_ready_for_enumeration() check to acpi_bus_attach() >> (replacing the acpi_device_is_present() check there) >> --- >> drivers/acpi/scan.c | 37 +++++++++++++++++++++++++++++++++---- >> include/acpi/acpi_bus.h | 5 ++++- >> 2 files changed, 37 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c >> index 5b54c80b9d32..8a4cf12f8453 100644 >> --- a/drivers/acpi/scan.c >> +++ b/drivers/acpi/scan.c >> @@ -796,6 +796,12 @@ static const char * const acpi_ignore_dep_ids[] = { >> NULL >> }; >> >> +/* List of HIDs for which we honor deps of matching ACPI devs, when checking _DEP lists. */ >> +static const char * const acpi_honor_dep_ids[] = { >> + "INT3472", /* Camera sensor PMIC / clk and regulator info */ >> + NULL >> +}; >> + >> static struct acpi_device *acpi_bus_get_parent(acpi_handle handle) >> { >> struct acpi_device *device = NULL; >> @@ -1757,8 +1763,12 @@ static void acpi_scan_dep_init(struct acpi_device *adev) >> struct acpi_dep_data *dep; >> >> list_for_each_entry(dep, &acpi_dep_list, node) { >> - if (dep->consumer == adev->handle) >> + if (dep->consumer == adev->handle) { >> + if (dep->honor_dep) >> + adev->flags.honor_deps = 1; >> + >> adev->dep_unmet++; >> + } >> } >> } >> >> @@ -1962,7 +1972,7 @@ static u32 acpi_scan_check_dep(acpi_handle handle, bool check_dep) >> for (count = 0, i = 0; i < dep_devices.count; i++) { >> struct acpi_device_info *info; >> struct acpi_dep_data *dep; >> - bool skip; >> + bool skip, honor_dep; >> >> status = acpi_get_object_info(dep_devices.handles[i], &info); >> if (ACPI_FAILURE(status)) { >> @@ -1971,6 +1981,7 @@ static u32 acpi_scan_check_dep(acpi_handle handle, bool check_dep) >> } >> >> skip = acpi_info_matches_ids(info, acpi_ignore_dep_ids); >> + honor_dep = acpi_info_matches_ids(info, acpi_honor_dep_ids); >> kfree(info); >> >> if (skip) >> @@ -1984,6 +1995,7 @@ static u32 acpi_scan_check_dep(acpi_handle handle, bool check_dep) >> >> dep->supplier = dep_devices.handles[i]; >> dep->consumer = handle; >> + dep->honor_dep = honor_dep; >> >> mutex_lock(&acpi_dep_list_lock); >> list_add_tail(&dep->node , &acpi_dep_list); >> @@ -2150,8 +2162,8 @@ static void acpi_bus_attach(struct acpi_device *device, bool first_pass) >> register_dock_dependent_device(device, ejd); >> >> acpi_bus_get_status(device); >> - /* Skip devices that are not present. */ >> - if (!acpi_device_is_present(device)) { >> + /* Skip devices that are not ready for enumeration (e.g. not present) */ >> + if (!acpi_dev_ready_for_enumeration(device)) { >> device->flags.initialized = false; >> acpi_device_clear_enumerated(device); >> device->flags.power_manageable = 0; >> @@ -2313,6 +2325,23 @@ void acpi_dev_clear_dependencies(struct acpi_device *supplier) >> } >> EXPORT_SYMBOL_GPL(acpi_dev_clear_dependencies); >> >> +/** >> + * acpi_dev_ready_for_enumeration - Check if the ACPI device is ready for enumeration >> + * @device: Pointer to the &struct acpi_device to check >> + * >> + * Check if the device is present and has no unmet dependencies. >> + * >> + * Return true if the device is ready for enumeratino. Otherwise, return false. >> + */ >> +bool acpi_dev_ready_for_enumeration(const struct acpi_device *device) >> +{ >> + if (device->flags.honor_deps && device->dep_unmet) >> + return false; >> + >> + return acpi_device_is_present(device); >> +} >> +EXPORT_SYMBOL_GPL(acpi_dev_ready_for_enumeration); >> + >> /** >> * acpi_dev_get_first_consumer_dev - Return ACPI device dependent on @supplier >> * @supplier: Pointer to the dependee device >> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h >> index 13d93371790e..2da53b7b4965 100644 >> --- a/include/acpi/acpi_bus.h >> +++ b/include/acpi/acpi_bus.h >> @@ -202,7 +202,8 @@ struct acpi_device_flags { >> u32 coherent_dma:1; >> u32 cca_seen:1; >> u32 enumeration_by_parent:1; >> - u32 reserved:19; >> + u32 honor_deps:1; >> + u32 reserved:18; >> }; >> >> /* File System */ >> @@ -284,6 +285,7 @@ struct acpi_dep_data { >> struct list_head node; >> acpi_handle supplier; >> acpi_handle consumer; >> + bool honor_dep; >> }; >> >> /* Performance Management */ >> @@ -693,6 +695,7 @@ static inline bool acpi_device_can_poweroff(struct acpi_device *adev) >> bool acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *uid2); >> >> void acpi_dev_clear_dependencies(struct acpi_device *supplier); >> +bool acpi_dev_ready_for_enumeration(const struct acpi_device *device); >> struct acpi_device *acpi_dev_get_first_consumer_dev(struct acpi_device *supplier); >> struct acpi_device * >> acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv); >> -- >> 2.31.1 >> >