Den 07.11.2022 11.21, skrev Maxime Ripard: > Hi Noralf, > > I'll leave aside your comments on the code, since we'll use your implementation. > > On Sun, Nov 06, 2022 at 05:33:48PM +0100, Noralf Trønnes wrote: >> Den 26.10.2022 17.33, skrev maxime@xxxxxxxxxx: >>> + >>> + if (cmdline->tv_mode_specified) >>> + default_mode = cmdline->tv_mode; >> >> I realised that we don't verify tv_mode coming from the command line, >> not here and not in the reset helper. Should we do that? A driver should >> be programmed defensively to handle an illegal/unsupported value, but it >> doesn't feel right to allow an illegal enum value coming through the >> core/helpers. > > I don't think we can end up with an invalid value here if it's been > specified. > > We parse the command line through drm_mode_parse_tv_mode() (introduced > in patch 13 "drm/modes: Introduce the tv_mode property as a command-line > option") that will pick the tv mode part of the command line, and call > drm_get_tv_mode_from_name() using it. > > drm_get_tv_mode_from_name() will return a EINVAL if it's not a value we > expect, and mode->tv_mode is only set on success. And AFAIK, there's no > other path that will set tv_mode. > I see now that illegal was the wrong word, but if the driver only supports ntsc, the user can still set tv_mode=PAL right? And that's an unsupported value that the driver can't fulfill, so it errors out. But then again maybe that's just how it is, we can also set a display mode that the driver can't handle, so this is no different in that respect. Yeah, my argument lost some of its strength here :) Noralf.
