On 17/03/17 07:01 PM, Ville Syrjälä wrote: > On Fri, Mar 17, 2017 at 06:01:41PM +0900, Michel Dänzer wrote: >> On 16/03/17 07:09 PM, Ville Syrjälä wrote: >>> On Thu, Mar 16, 2017 at 06:55:53PM +0900, Michel Dänzer wrote: >>>> From: Michel Dänzer <michel.daenzer@xxxxxxx> >>>> >>>> Otherwise this can also prevent modesets e.g. for switching VTs. >>>> >>>> FB_MISC_USER_EVENT is set when the request originates from userspace, >>>> which is what we're interested in here according to the DRM_DEBUG >>>> output. >>> >>> So why is the kernel allowed to violate this? >>> >>> The checks look somewhat bogus to me anyway. The 'virtual size == fb size' >>> check makes some kind of sense. Although I don't see why the virtual >>> resolution couldn't be smaller than the fb size. But requiring that the >>> visible resolutionn matches the fb size as well definitely seems wrong. >> >> Agreed on all counts. So, I think what's needed is almost a revert of >> 865afb11949e, except for the bits_per_pixel comparison, since we really >> can't change that. See diff below. > > So one semi-crazy idea I had was: > 12:18 < vsyrjala> daniels: hmm. given that the fb_helper doesn't > implement a modeset in set_par, i guess what we really > should do is look at the currently active crtcs and see if the mode on > one of them more or less matches what the user is asking for I don't get the idea. What's the point of comparing the var->* values to whatever is currently active in the hardware? The purpose of the code is to check that the requested parameters fit into fb_helper's framebuffer. > I tried to trip this current check by booting with a big screen and > later switching to a small screen. For some reason that worked out > just fine, I'd need more details about what exactly you tried. > so I'm not even sure what kind of values we stuff into xres & co. It should be the values shown / attempted to set by fbset. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
