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FromBjorn Helgaas <>
SubjectRe: [PATCH] PNPACPI: cope with invalid device IDs
DateFri, 4 Jun 2010 11:23:22 -0600
On Friday, June 04, 2010 02:04:32 am Dmitry Torokhov wrote:
> If primary ID (HID) is invalid try locating first valid ID on compatible
> ID list before giving up. This helps, for example, to recognize i8042 AUX
> port on Sony Vaio VPCZ1 which uses SNYSYN0003 as HID.

Is there a bugzilla report or mailing list discussion you could point
to here (in the changelog)?

> Tested-by: Jan-Hendrik Zab <jan@jhz.name>
> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
> ---
>
> drivers/pnp/pnpacpi/core.c | 27 +++++++++++++++++++++++----
> 1 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
> index f7ff628..1bf1677 100644
> --- a/drivers/pnp/pnpacpi/core.c
> +++ b/drivers/pnp/pnpacpi/core.c
> @@ -28,7 +28,7 @@
> #include "../base.h"
> #include "pnpacpi.h"
>
> -static int num = 0;
> +static int num;

Unrelated change, but OK by me :-)

> /* We need only to blacklist devices that have already an acpi driver that
> * can't use pnp layer. We don't need to blacklist device that are directly
> @@ -157,11 +157,24 @@ struct pnp_protocol pnpacpi_protocol = {
> };
> EXPORT_SYMBOL(pnpacpi_protocol);
>
> +static char *pnpacpi_get_id(struct acpi_device *device)
> +{
> + struct acpi_hardware_id *id;
> +
> + list_for_each_entry(id, &device->pnp.ids, list) {
> + if (ispnpidacpi(id->id))
> + return id->id;
> + }
> +
> + return NULL;
> +}
> +
> static int __init pnpacpi_add_device(struct acpi_device *device)
> {
> acpi_handle temp = NULL;
> acpi_status status;
> struct pnp_dev *dev;
> + char *pnpid;
> struct acpi_hardware_id *id;
>
> /*
> @@ -169,11 +182,17 @@ static int __init pnpacpi_add_device(struct acpi_device *device)
> * driver should not be loaded.
> */
> status = acpi_get_handle(device->handle, "_CRS", &temp);
> - if (ACPI_FAILURE(status) || !ispnpidacpi(acpi_device_hid(device)) ||
> - is_exclusive_device(device) || (!device->status.present))
> + if (ACPI_FAILURE(status))
> + return 0;
> +
> + pnpid = pnpacpi_get_id(device);
> + if (!pnpid)
> + return 0;

This part (run ispnpidacpi() on all _HIDs & _CIDs, not just on _HID,
so we'll now build a PNPACPI device for things with an invalid _HID
but a valid _CID) makes sense to me and is probably required for the
i8042 PNP driver to claim the device.

> +
> + if (!is_exclusive_device(device) || !device->status.present)
> return 0;
>
> - dev = pnp_alloc_dev(&pnpacpi_protocol, num, acpi_device_hid(device));
> + dev = pnp_alloc_dev(&pnpacpi_protocol, num, pnpid);

I'm curious about this part. Does it fix something?

Let's say this device has _HID=SNYSYN0003, _CID=PNP0F13.

Previously, we didn't make a PNP device at all because SNYSYN0003 is
invalid. Now, we'll make a device, exclude SNYSYN0003 from the PNP ID
list, and it looks like the loop farther down will add PNP0f13 again,
so we'll end up with "PNP0f13 PNP0f13" (I think I mentioned this when
reviewing an earlier version of the patch :-)).

With the original pnp_alloc_dev(acpi_device_hid()) call, we'll probably
end up with "SNYsyn0 PNP0f13". That's clearly wrong, too.

For now, I think the best fix is to keep this pnp_alloc_dev() call change
and adjust the loop so it doesn't add "pnpid" again, so we end up with
just "PNP0f13".

In the long term, I wonder if it'd be better to quit checking the ID for
validity and make pnp_id.id a pointer rather than an array, so we could
have "SNYSYN0003 PNP0f13" as PNP IDs for this device. I bet that's what
Windows does.

Bjorn


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