Messages in this thread | | | From | Vihas Mak <> | Date | Tue, 9 Nov 2021 16:08:52 +0530 | Subject | |
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> On Tue, Nov 09, 2021 at 12:28:18AM +0530, Vihas Mak wrote: > > Make sure the mode is a valid IEEE1284 mode. > What is a valid mode?
The valid IEEE1284 modes are the ones defined in <uapi/linux/parport.h>. Currently there are 10 modes. Namely nibble mode, byte mode, ECP, ECPRLE, EPP and some specials.
> How did you test this? And why is this needed now? What hardware was > working that is now not going to work with this driver?
I tested this on my local pc using a parallel port and read the incoming data on my Raspberry PI. I also used https://github.com/strezh/VPPSniffer. It's a simple virtual parallel port used for debugging and sniffing.
The mainline code wasn't validating the mode when a user-space program does a ioctl call to change the current mode. It might create some bugs if the new mode isn't one of the IEEE1284 modes defined in <uapi/linux/parport.h>. So it's better to throw a EINVAL beforehand, if the mode is invalid.
> > +static int pp_validate_mode(int mode) > bool?
My bad. Will do a v2.
Thanks, Vihas
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