On Sep 08 2014 or thereabouts, Jiri Kosina wrote: > On Fri, 5 Sep 2014, Benjamin Tissoires wrote: > > > In the Dell XPS 13 9333, it appears that sometimes the bus get confused > > and corrupts the incoming data. It fills the input report with the > > sentinel value "ff". Synaptics told us that such behavior does not comes > > from the touchpad itself, so we filter out such reports here. > > > > Unfortunately, we can not simply discard the incoming data because they > > may contain useful information. Most of the time, the misbehavior is > > quite near the end of the report, so we can still use the valid part of > > it. > > > > Fixes: > > https://bugzilla.redhat.com/show_bug.cgi?id=1123584 > > > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > > --- > > drivers/hid/hid-rmi.c | 31 ++++++++++++++++++++++++++----- > > 1 file changed, 26 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c > > index 8389e81..db92c3b 100644 > > --- a/drivers/hid/hid-rmi.c > > +++ b/drivers/hid/hid-rmi.c > > @@ -320,9 +320,6 @@ static int rmi_f11_input_event(struct hid_device *hdev, u8 irq, u8 *data, > > int offset; > > int i; > > > > - if (size < hdata->f11.report_size) > > - return 0; > > - > > if (!(irq & hdata->f11.irq_mask)) > > return 0; > > > > @@ -332,9 +329,13 @@ static int rmi_f11_input_event(struct hid_device *hdev, u8 irq, u8 *data, > > int fs_bit_position = (i & 0x3) << 1; > > int finger_state = (data[fs_byte_position] >> fs_bit_position) & > > 0x03; > > + int position = offset + 5 * i; > > + > > + if (position + 5 > size) > > + /* partial report, go on with what we received */ > > + break; > > Do you perhaps want to warn the user here, so that he knows that things > are getting a little bit hairy? Or is this happening so often that it > makes no sense to warn about it? > I wanted to check on that yesterday, but I have been side tracked quite a lot. So: I think there might be too much messages to unconditionally notify the user here. I do not see a better way than limiting the number to 10 or so before giving up the notifications. Ideally, I would love to notify the user when useful information is lost, but I did not came up with a solution quickly. On the other hand, not having the coordinates is not that much of a problem I think. But, missing a f30 message (button event) is much more of a problem, and I think we should notify the user there unconditionally because there will be stuck pointers if the failure happens during a release. v2 should be on its way something like next week unless somebody else wants to take over. Cheers, Benjamin -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
