From 22c13f9d8179f4c9caecfcb60a95214562b9addc Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 1 Aug 2008 17:37:54 +0200 Subject: ACPI: video: Ignore devices that aren't present in hardware This is a reimplemention of commit 0119509c4fbc9adcef1472817fda295334612976 from Matthew Garrett This patch got removed because of a regression: ThinkPads with a Intel graphics card and an Integrated Graphics Device BIOS implementation stopped working. In fact, they only worked because the ACPI device of the discrete, the wrong one, got used (via int10). So ACPI functions were poking on the wrong hardware used which is a sever bug. The next patch provides support for above ThinkPads to be able to switch brightness via the legacy thinkpad_acpi driver and automatically detect when to use it. Original commit message from Matthew Garrett: Vendors often ship machines with a choice of integrated or discrete graphics, and use the same DSDT for both. As a result, the ACPI video module will locate devices that may not exist on this specific platform. Attempt to determine whether the device exists or not, and abort the device creation if it doesn't. http://bugzilla.kernel.org/show_bug.cgi?id=9614 Signed-off-by: Thomas Renninger Acked-by: Zhang Rui Signed-off-by: Andi Kleen Signed-off-by: Len Brown --- drivers/acpi/glue.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'drivers/acpi/glue.c') diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c index 24649ada08d..adec3d15810 100644 --- a/drivers/acpi/glue.c +++ b/drivers/acpi/glue.c @@ -140,6 +140,46 @@ struct device *acpi_get_physical_device(acpi_handle handle) EXPORT_SYMBOL(acpi_get_physical_device); +/* ToDo: When a PCI bridge is found, return the PCI device behind the bridge + * This should work in general, but did not on a Lenovo T61 for the + * graphics card. But this must be fixed when the PCI device is + * bound and the kernel device struct is attached to the acpi device + * Note: A success call will increase reference count by one + * Do call put_device(dev) on the returned device then + */ +struct device *acpi_get_physical_pci_device(acpi_handle handle) +{ + struct device *dev; + long long device_id; + acpi_status status; + + status = + acpi_evaluate_integer(handle, "_ADR", NULL, &device_id); + + if (ACPI_FAILURE(status)) + return NULL; + + /* We need to attempt to determine whether the _ADR refers to a + PCI device or not. There's no terribly good way to do this, + so the best we can hope for is to assume that there'll never + be a device in the host bridge */ + if (device_id >= 0x10000) { + /* It looks like a PCI device. Does it exist? */ + dev = acpi_get_physical_device(handle); + } else { + /* It doesn't look like a PCI device. Does its parent + exist? */ + acpi_handle phandle; + if (acpi_get_parent(handle, &phandle)) + return NULL; + dev = acpi_get_physical_device(phandle); + } + if (!dev) + return NULL; + return dev; +} +EXPORT_SYMBOL(acpi_get_physical_pci_device); + static int acpi_bind_one(struct device *dev, acpi_handle handle) { struct acpi_device *acpi_dev; -- cgit v1.2.3