On Wed, Feb 10, 2021 at 12:51 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> We allow to read the single value as a first element in the array.
> Unfortunately the counting doesn't work in this case and we can't
> call fwnode_property_count_*() API without getting an error.
It would be good to mention what the symptom of the issue is here.
> Modify acpi_data_prop_read() to always try the single value read
> and thus allow counting the single value as an array of 1 element.
>
> Reported-by: Calvin Johnson <calvin.johnson@xxxxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
This is a bug fix, so it should go in before the cleanups in this series IMO.
Also it looks like stable@vger material.
> ---
> drivers/acpi/property.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index 236316ee0e25..d6100585fceb 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -913,12 +913,14 @@ static int acpi_data_prop_read(const struct acpi_device_data *data,
> const union acpi_object *items;
> int ret;
>
> - if (val && nval == 1) {
> + /* Try to read as a single value first */
> + if (!val || nval == 1) {
> ret = acpi_data_prop_read_single(data, propname, proptype, val);
This returns -EINVAL if val is NULL.
> if (ret >= 0)
> - return ret;
> + return val ? ret : 1;
So val cannot be NULL here.
> }
>
> + /* It's not the single value, get an array instead */
> ret = acpi_data_get_property_array(data, propname, ACPI_TYPE_ANY, &obj);
> if (ret)
> return ret;
> --
To me, acpi_fwnode_property_read_string_array() needs to special-case
val == NULL and nval == 0.
