On Wed, Dec 9, 2020 at 4:08 AM Hui Wang <hui.wang@xxxxxxxxxxxxx> wrote:
>
>
> On 12/8/20 10:01 PM, Rafael J. Wysocki wrote:
> > On Tue, Dec 8, 2020 at 3:02 AM Hui Wang <hui.wang@xxxxxxxxxxxxx> wrote:
> >>
> >> On 12/7/20 9:11 PM, Rafael J. Wysocki wrote:
> >>> On Fri, Dec 4, 2020 at 8:51 AM Hui Wang <hui.wang@xxxxxxxxxxxxx> wrote:
> > [cut]
> >
> >>> Would dropping the device ID in question from acpi_pnp_device_ids[]
> >>> make the problem go away?
> >>>
> >>> If so, why don't you do just that?
> >> Yes, if remove "WACFXXX" from acpi_pnp_device_ids[], could fix this
> >> issue. I planned to do so, but I found the pnp_driver in the
> >> drivers/tty/serial/8250/8250_pnp.c still handle this ID, maybe it could
> >> introduce regression on old machines if removing it.
> > Well, "WACFXXX" is not a proper device ID, it is a wild card possibly
> > matching too many devices.
> >
> > What device ID specifically is used in the ACPI tables for the device
> > in question?
>
> It is "WACF2200", how about the change as below, is it safe to say the
> length of a pnp device id is 7?
>
> diff --git a/drivers/acpi/acpi_pnp.c b/drivers/acpi/acpi_pnp.c
> index 4ed755a963aa..1e828378238c 100644
> --- a/drivers/acpi/acpi_pnp.c
> +++ b/drivers/acpi/acpi_pnp.c
> @@ -336,6 +336,10 @@ static bool acpi_pnp_match(const char *idstr, const
> struct acpi_device_id **matc
> {
> const struct acpi_device_id *devid;
>
> + /* Expect the pnp device id has CCCdddd format (C character, d
> digital) */
> + if (strlen(idstr) != 7)
> + return false;
> +
> for (devid = acpi_pnp_device_ids; devid->id[0]; devid++)
> if (matching_id(idstr, (char *)devid->id)) {
> if (matchid)
Alternatively, matching_id() can be updated to compare the length
(which arguably it should be doing).
