On Tuesday, February 10, 2015 11:59:32 AM Mika Westerberg wrote:
On Mon, Feb 09, 2015 at 09:02:11PM +0000, Suthikulpanit, Suravee wrote:
On 2/9/15, 19:15, "Mika Westerberg" mika.westerberg@linux.intel.com wrote:
On Mon, Feb 09, 2015 at 12:02:43AM +0100, Rafael J. Wysocki wrote:
On Monday, February 09, 2015 12:20:03 AM Suravee Suthikulpanit wrote:
Device drivers typically use ACPI _HIDs/_CIDs listed in struct
device_driver
acpi_match_table to match devices. However, for generic drivers, we do not want to list _HID for all supported devices, and some device
classes
do not have _CID (e.g. SATA, USB). Instead, we can leverage ACPI _CLS, which specifies PCI-defined class code (i.e. base-class, subclass and programming interface).
This patch adds support for matching ACPI devices using the _CLS
method.
Signed-off-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com
Greg, Mika, any problems with this?
Is there some specific reason why this cannot be done in similar way than PCI already does?
In other words, stuff _CLS fields to struct acpi_device_id and make match functions match against those if they are != 0.
That was my original thought. Then I realized that the acpi_device_id is used to create the device matching table, in which could contain several _HID/_CID. However, most of the added _CLS field would likely ended up being unused and taking up space.
Well, PCI is doing that already :)
In contrast to _HID/_CID, a driver is likely to match just a single _CLS. So, I think it is cleaner to have just a dedicate struct acpi_device_cls, and a matching function for it.
IMHO cleaner version is the one following PCI.
I agree.
Besides, how do you support modules with this? Or did I miss something?
Good question.