On Tuesday, April 25, 2017, Jason Gerecke <killertofu@xxxxxxxxx> wrote:
>
> The following Smatch complaint was generated in response to commit
> 2a6cdbd ("HID: wacom: Introduce new 'touch_input' device"):
>
> drivers/hid/wacom_wac.c:1586 wacom_tpc_irq()
> error: we previously assumed 'wacom->touch_input' could be null (see line 1577)
>
> The 'touch_input' and 'pen_input' variables point to the 'struct input_dev'
> used for relaying touch and pen events to userspace, respectively. If a
> device does not have a touch interface or pen interface, the associated
> input variable is NULL. The 'wacom_tpc_irq()' function is responsible for
> forwarding input reports to a more-specific IRQ handler function. An
> unknown report could theoretically be mistaken as e.g. a touch report
> on a device which does not have a touch interface. This can be prevented
> by only calling the pen/touch functions are called when the pen/touch
> pointers are valid.
>
> Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx>
Reviewed-by: Ping Cheng <ping.cheng@xxxxxxxxx>
Looks good to me.
Cheers,
Ping
>
> ---
> drivers/hid/wacom_wac.c | 45 +++++++++++++++++++++++----------------------
> 1 file changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
> index 6b8f6b816195..b963499e3351 100644
> --- a/drivers/hid/wacom_wac.c
> +++ b/drivers/hid/wacom_wac.c
> @@ -1571,37 +1571,38 @@ static int wacom_tpc_irq(struct wacom_wac *wacom, size_t len)
> {
> unsigned char *data = wacom->data;
>
> - if (wacom->pen_input)
> + if (wacom->pen_input) {
> dev_dbg(wacom->pen_input->dev.parent,
> "%s: received report #%d\n", __func__, data[0]);
> - else if (wacom->touch_input)
> +
> + if (len == WACOM_PKGLEN_PENABLED ||
> + data[0] == WACOM_REPORT_PENABLED)
> + return wacom_tpc_pen(wacom);
> + }
> + else if (wacom->touch_input) {
> dev_dbg(wacom->touch_input->dev.parent,
> "%s: received report #%d\n", __func__, data[0]);
>
> - switch (len) {
> - case WACOM_PKGLEN_TPC1FG:
> - return wacom_tpc_single_touch(wacom, len);
> + switch (len) {
> + case WACOM_PKGLEN_TPC1FG:
> + return wacom_tpc_single_touch(wacom, len);
>
> - case WACOM_PKGLEN_TPC2FG:
> - return wacom_tpc_mt_touch(wacom);
> + case WACOM_PKGLEN_TPC2FG:
> + return wacom_tpc_mt_touch(wacom);
>
> - case WACOM_PKGLEN_PENABLED:
> - return wacom_tpc_pen(wacom);
> + default:
> + switch (data[0]) {
> + case WACOM_REPORT_TPC1FG:
> + case WACOM_REPORT_TPCHID:
> + case WACOM_REPORT_TPCST:
> + case WACOM_REPORT_TPC1FGE:
> + return wacom_tpc_single_touch(wacom, len);
>
> - default:
> - switch (data[0]) {
> - case WACOM_REPORT_TPC1FG:
> - case WACOM_REPORT_TPCHID:
> - case WACOM_REPORT_TPCST:
> - case WACOM_REPORT_TPC1FGE:
> - return wacom_tpc_single_touch(wacom, len);
> -
> - case WACOM_REPORT_TPCMT:
> - case WACOM_REPORT_TPCMT2:
> - return wacom_mt_touch(wacom);
> + case WACOM_REPORT_TPCMT:
> + case WACOM_REPORT_TPCMT2:
> + return wacom_mt_touch(wacom);
>
> - case WACOM_REPORT_PENABLED:
> - return wacom_tpc_pen(wacom);
> + }
> }
> }
>
> --
> 2.12.2
>
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