Hi, On my Corsair K70 keyboard, when pressing some key and then the backslash key (KEY_BACKSLASH) in rapid succession the backslash character will be repeated three times. This bug has been mentioned on this list before (by Norbert Veber on the 24th of februrary) but there was no responses, also Norbert consider it a problem with Corsair keyboards but as I describe below I feel it is more of a general problem in the HID input code. This bug is discussed on the Corsair forums, but it seems the exact same thing also happens with Gigabyte Osmium and QPAD MK85, possibly it is a problem on all keyboards supporting n-key rollover. I believe the root cause of this is that the keyboard reports all keys including both HID keys 0x31 and 0x32 which are both mapped to KEY_BACKSLASH in hid-input.c. I am using a nordic keyboard meaning KEY_BACKSLASH is labeled "apostrophe" and that HID key 0x32 is reported. A US keyboard has a backslash key which should report 0x31. I have added some traces before the input_event call at the end of hidinput_report_event. When pressing A key and then apostrophe, something like this is seen (omitting all inactive keys): VALUE 1 CODE 30 HID 0x4 VALUE 0 CODE 43 HID 0x31 VALUE 0 CODE 43 HID 0x32 Output: a VALUE 1 CODE 30 HID 0x4 VALUE 0 CODE 43 HID 0x31 VALUE 1 CODE 43 HID 0x32 Output: ' VALUE 0 CODE 30 HID 0x4 VALUE 0 CODE 43 HID 0x31 VALUE 1 CODE 43 HID 0x32 Output: ' VALUE 0 CODE 30 HID 0x4 VALUE 0 CODE 43 HID 0x31 VALUE 1 CODE 43 HID 0x32 Output: ' VALUE 0 CODE 30 HID 0x4 VALUE 0 CODE 43 HID 0x31 VALUE 0 CODE 43 HID 0x32 So the fact that 0x31 is inactive will cause bad release events on key 43 to be sent. I have made a simple patch that tracks which of the two variants is active and ignores the other one. It works but I don't have much knowledge on HID input so before posting it would like to know if someone has input on how to do a cleaner fix. I am happy to help with testing or implementation if I am able. Regards, Fredrik -- 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
