Just making sure this doesn't get lost in the cracks.

Jason
---
Now instead of four in the eights place /
you’ve got three, ‘Cause you added one  /
(That is to say, eight) to the two,     /
But you can’t take seven from three,    /
So you look at the sixty-fours....



On Tue, Apr 25, 2017 at 1:56 PM, Ping Cheng [off-list ref] wrote:

On Tuesday, April 25, 2017, Jason Gerecke [off-list ref] wrote:

quoted

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@wacom.com>

Reviewed-by: Ping Cheng <ping.cheng@wacom.com>

Looks good to me.

Cheers,
Ping

quoted

---
 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