On 2/10/15, 23:07, "Rafael J. Wysocki" rjw@rjwysocki.net wrote:
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
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.
Ok, let me reimplement this part to put "u32 cls" in the struct acpi_device_id, and use that for matching then.
Besides, how do you support modules with this? Or did I miss something?
Good question.
Ah. I didn¹t think about this part earlier.
IIUC, the current ACPI driver would create modules.alias entry with format: acpi:<HID>:<CID>
What do you think if we append the _CLS of the device using the following format: acpi:<HID>:<CID>:<CLS>
In case of PCI_CLASS_STORAGE_SATA_AHCI, this would become: acpi:::0x10601
Thanks,
Suravee