Re: Buffer overrun in the TWL4030 keypad driver with Nokia RX51

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Dmitry,

On Saturday 17 July 2010 23:37:05 Dmitry Torokhov wrote:
> On Fri, Jul 16, 2010 at 05:28:43PM +0200, Laurent Pinchart wrote:
> > 
> > I've spent the day debugging a kernel crash in the USB networking code to
> > find out the problem was caused by a buffer overrun in the TWL4030
> > keypad driver.
> > 
> > The Nokia RX51 board code (arch/arm/mach-omap2/board-rx51-peripherals.c)
> > defines a key map for the matrix keypad keyboard. The hardware seems to
> > use all of the 8 rows and 8 columns of the keypad, although not all
> > possible locations are used.
> > 
> > The TWL4030 supports keypads with at most 8 rows and 8 columns. Most keys
> > are defined with a row and column number between 0 and 7, except
> > 
> >         KEY(0xff, 2, KEY_F9),
> >         KEY(0xff, 4, KEY_F10),
> >         KEY(0xff, 5, KEY_F11),
> > 
> > The row number is set to 0xff. As the generic matrix keypad support
> > (include/linux/input/matrix_keypad.h) supports at most 16 rows and 16
> > columns, it masks all but the lower 4 bits of the row and column numbers
> > in the KEY macro.
> 
> [..snipped..]
> 
> Thanks for the report. Could yo uplease try the patch below and let me
> know if it works.

The patch fixes the crash at startup, but the F9, F10 and F11 key events are 
never reported. That might be because those keys are not wired up to anything 
though. All keys on the keyboard, as well as the F7 and F8 keys (volume up and 
down on the of the case) generate the proper events. All other "keys" 
(keyboard slider switch, power button, focus button, lock switch, proximity 
sensor) report events through other devices.

> I have some concerns with the keymap assignments, I see that Amit
> changed them during KEY(col, row) -> KEY(row, col) conversion. I marked
> the entries I am concerned with with XXX.

F7, F8, right alt and left shift are properly mapped. I don't know what F9, 
F10 and F11 are supposed to be.

-- 
Regards,

Laurent Pinchart