On Fri, May 26, 2017 at 08:40:28AM -0700, Nick Desaulniers wrote: > Clang warns: > > drivers/input/mousedev.c:653:63: error: implicit conversion from 'int' > to 'signed char' changes value from 200 to -56 > [-Wconstant-conversion] > client->ps2[1] = 0x60; client->ps2[2] = 3; client->ps2[3] = 200; > ~ ^~~ > > As far as I can tell, from > > http://www.computer-engineering.org/ps2mouse/ > > Under "Command Set" > "0xE9 (Status Request)" > > the value 200 is a valid sample rate. Using unsigned char, rather than > signed char, for client->ps2 silences this warning. > > Signed-off-by: Nick Desaulniers <[email protected]> > --- > * Additionally change function signature for the lone function dealing > with ps2 data. > > drivers/input/mousedev.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c > index 0e0ff84088fd..0e31a109b1b4 100644 > --- a/drivers/input/mousedev.c > +++ b/drivers/input/mousedev.c > @@ -103,7 +103,7 @@ struct mousedev_client { > spinlock_t packet_lock; > int pos_x, pos_y; > > - signed char ps2[6]; > + unsigned char ps2[6]; > unsigned char ready, buffer, bufsiz; > unsigned char imexseq, impsseq; > enum mousedev_emul mode; > @@ -577,7 +577,7 @@ static inline int mousedev_limit_delta(int delta, int > limit) > } > > static void mousedev_packet(struct mousedev_client *client, > - signed char *ps2_data) > + unsigned char *ps2_data) > { > struct mousedev_motion *p = &client->packets[client->tail];
If you look at the code of this fucntion we really use ps2_data as signed in calculations, and this change would break that. While making ps2_data u8 might be beneficial we'd need to rework mousedev_packet() to use signed temporaries for dx, dy and dz before stufifng them into ps2_data. Thanks. -- Dmitry
