On Sat, 8 Feb 2025, Tomasz Pakuła wrote:
> As noted by Anssi some 20 years ago, pool report is sometimes messed up.
> This worked fine on many devices but casued oops on VRS DirectForce PRO.
>
> Here, we're making sure pool report is refetched before trying to access
> any of it's fields. While loop was replaced with a for loop + exit
> conditions were moved aroud to decrease the possibility of creating an
> infinite loop scenario.
>
> Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@xxxxxxxxx>
> ---
> drivers/hid/usbhid/hid-pidff.c | 34 ++++++++++++++++------------------
> 1 file changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
> index f23381b6e344..acdcc0af86ba 100644
> --- a/drivers/hid/usbhid/hid-pidff.c
> +++ b/drivers/hid/usbhid/hid-pidff.c
> @@ -604,28 +604,26 @@ static void pidff_reset(struct pidff_device *pidff)
> }
>
> /*
> - * Refetch pool report
> + * Fetch pool report
> */
> static void pidff_fetch_pool(struct pidff_device *pidff)
> {
> - if (!pidff->pool[PID_SIMULTANEOUS_MAX].value)
> - return;
> -
> - int i = 0;
> - while (pidff->pool[PID_SIMULTANEOUS_MAX].value[0] < 2) {
> - hid_dbg(pidff->hid, "pid_pool requested again\n");
> - hid_hw_request(pidff->hid, pidff->reports[PID_POOL],
> - HID_REQ_GET_REPORT);
> - hid_hw_wait(pidff->hid);
> -
> - /* break after 20 tries with SIMULTANEOUS_MAX < 2 */
> - if (i++ > 20) {
> - hid_warn(pidff->hid,
> - "device reports %d simultaneous effects\n",
> - pidff->pool[PID_SIMULTANEOUS_MAX].value[0]);
> - break;
> - }
> + int i;
> + struct hid_device *hid = pidff->hid;
> +
> + /* Try 20 times if PID_SIMULTANEOUS_MAX < 2.
> + We must make sure this isn't just an error */
Sorry for annoying nit: this is not really consistent with Kernel / HID
comment style :)
--
Jiri Kosina
SUSE Labs
