This series was prompted by an issue we saw recently in the mm tree: http://lkml.org/lkml/2009/7/20/422 Synopsis: Linux/ACPI discovered a video device. The device had no _HID or _CID methods, but based on acpi_is_video_device(), we added a sythetic CID ("LNXVIDEO"), so the device ended up with a CID but no HID. We bound the acpi_video_bus (drivers/acpi/video.c) driver to the device based on the CID. This driver has a .notify() method, so we tried to install a notify handler on the device. This uses strcmp() on the device HID to determine whether it's a fixed hardware device, and this oopsed because this device had no HID. This used to work because the HID was stored in an array that was initialized to zeroes, but a recent change replaced this with a pointer that is NULL until a HID is set. This thread: http://marc.info/?l=linux-acpi&m=124959955813409&w=2 has patches that work around this by basically returning a pointer to an empty string rather than a NULL pointer in this case. However, the HID is a pretty central part of an acpi_device, and I think it complicates the driver model too much to deal with HIDs that might be empty strings. I think it's better for Linux/ACPI to just make sure that *every* acpi_device has at least one ID (either a HID, a CID, or a synthetic ID). The main place this default "device" ID appears is with ACPI devices that just have _ADR methods, e.g., PCI slots. Original posting: http://marc.info/?l=linux-acpi&m=125113191017124&w=2 Changes from v2 to v3: - Refreshed to apply on current acpi-test (193a6dec1c0246a). Changes from initial post to v2: - Applies on acpi-test (on top of "ACPI: cleanups for hotplug", http://marc.info/?l=linux-acpi&m=125175792329288&w=2). - Removed memory leak fix (folded into v2 of series that introduced it). - Fixes the synthetic HID for \_SB_. This has been broken for a long time, so we've been seeing "device:00" instead of "LNXSYBUS" in sysfs. - Makes sure every acpi_device has a default "device" HID if nothing else. (We already used "device" in sysfs if we didn't have a HID or CID.) - Adds a single list containing the HID and any CIDs. No users make a distinction between them, so maintaining them separately just made things complicated. - Removes the _UID stuff, which nobody uses. --- Bjorn Helgaas (8): ACPI: fix synthetic HID for \_SB_ ACPI: use acpi_device_hid() when possible ACPI: make sure every acpi_device has an ID ACPI: maintain a single list of _HID and _CID IDs ACPI: remove acpi_device.flags.compatible_ids ACPI: remove acpi_device.flags.hardware_id ACPI: remove acpi_device_uid() and related stuff ACPI: simplify building device HID/CID list drivers/acpi/scan.c | 283 +++++++++++++------------------------------- drivers/pnp/pnpacpi/core.c | 21 +-- include/acpi/acpi_bus.h | 16 +- 3 files changed, 100 insertions(+), 220 deletions(-) -- Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
