On Mon, Feb 2, 2015 at 10:32 AM, Sébastien Bourdeauducq <sb@xxxxxxxxx> wrote: > On 02/02/2015 09:48 PM, Mika Westerberg wrote: >> On Mon, Feb 02, 2015 at 09:19:51PM +0800, Sebastien Bourdeauducq wrote: >>> With this computer nothing is normal. Every single component except the CPU, >>> display and USB has major issues under Linux. >> >> We need to get one here then. Can you point me to the exact model? > > That's a Lenovo Thinkpad Tablet 10, P/N 20C3001VHH. What would be the > plan for you to get one? > >> Since it has 20k internal pull-up configured, I'm guessing something >> (the digitizer) drives it low like it still has something to report. Do >> you see in the dmesg if the i2c-hid.c is able to read reports from the >> device? > > When I made the interrupt falling edge sensitive, i2c-hid was able to > read the first report as I could move the mouse cursor once using the > stylus. > > A possible scenario is: > 1) the digitizer is holding the interrupt line low after booting > 2) enumerating or otherwise initializing the digitizer causes it to > release the interrupt line > 3) using the stylus queues several reports in the device and it asserts > the interrupt line again. However, with the interrupt configured as edge > sensitive, only the first of those reports are retrieved and subsequent > ones are lost, with the interrupt line stuck. There has been a patch floating around last year which tried to pull all the available reports after the IRQ was triggered. I rejected it for the sake of not breaking existing devices, but maybe your device needs it. http://www.spinics.net/lists/linux-input/msg31342.html Cheers, Benjamin > > Maybe the interrupt should be level sensitive and enabled only after > certain parts of the device initialization have taken place. > > Sébastien > -- 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
