From: Gerd Hoffmann <kraxel@redhat.com> To: "Michel Dänzer" <michel@daenzer.net> Cc: dri-devel@lists.freedesktop.org, open list <linux-kernel@vger.kernel.org>, amd-gfx@lists.freedesktop.org, Daniel Vetter <daniel.vetter@intel.com> Subject: Re: [PATCH 3/6] drm: fourcc byteorder: add bigendian support to drm_mode_legacy_fb_format Date: Wed, 26 Apr 2017 07:53:10 +0200 [thread overview] Message-ID: <1493185990.23739.7.camel@redhat.com> (raw) In-Reply-To: <3b872a56-80b5-0c44-712f-a9517489eb24@daenzer.net> On Di, 2017-04-25 at 12:18 +0900, Michel Dänzer wrote: > On 24/04/17 03:25 PM, Gerd Hoffmann wrote: > > Return correct fourcc codes on bigendian. Drivers must be adapted to > > this change. > > > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> > > Just to reiterate, this won't work for the radeon driver, which programs > the GPU to use (effectively, per the current definition that these are > little endian GPU formats) DRM_FORMAT_XRGB8888 with pre-R600 and > DRM_FORMAT_BGRX8888 with >= R600. Hmm, ok, how does bigendian fbdev emulation work on pre-R600 then? > > +#ifdef __BIG_ENDIAN > > + switch (bpp) { > > + case 8: > > + fmt = DRM_FORMAT_C8; > > + break; > > + case 24: > > + fmt = DRM_FORMAT_BGR888; > > + break; > > BTW, endianness as a concept cannot apply to 8 or 24 bpp formats. I could move the 8 bpp case out of the #ifdef somehow, but code readability will suffer then I think ... For 24 we have different byte orderings, but yes, you can't switch from one to the other with byteswapping. Probably one of the reasons why this format is pretty much out of fashion these days ... cheers, Gerd
WARNING: multiple messages have this Message-ID (diff)
From: Gerd Hoffmann <kraxel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> To: "Michel Dänzer" <michel-otUistvHUpPR7s880joybQ@public.gmane.org> Cc: Daniel Vetter <daniel.vetter-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Subject: Re: [PATCH 3/6] drm: fourcc byteorder: add bigendian support to drm_mode_legacy_fb_format Date: Wed, 26 Apr 2017 07:53:10 +0200 [thread overview] Message-ID: <1493185990.23739.7.camel@redhat.com> (raw) In-Reply-To: <3b872a56-80b5-0c44-712f-a9517489eb24-otUistvHUpPR7s880joybQ@public.gmane.org> On Di, 2017-04-25 at 12:18 +0900, Michel Dänzer wrote: > On 24/04/17 03:25 PM, Gerd Hoffmann wrote: > > Return correct fourcc codes on bigendian. Drivers must be adapted to > > this change. > > > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> > > Just to reiterate, this won't work for the radeon driver, which programs > the GPU to use (effectively, per the current definition that these are > little endian GPU formats) DRM_FORMAT_XRGB8888 with pre-R600 and > DRM_FORMAT_BGRX8888 with >= R600. Hmm, ok, how does bigendian fbdev emulation work on pre-R600 then? > > +#ifdef __BIG_ENDIAN > > + switch (bpp) { > > + case 8: > > + fmt = DRM_FORMAT_C8; > > + break; > > + case 24: > > + fmt = DRM_FORMAT_BGR888; > > + break; > > BTW, endianness as a concept cannot apply to 8 or 24 bpp formats. I could move the 8 bpp case out of the #ifdef somehow, but code readability will suffer then I think ... For 24 we have different byte orderings, but yes, you can't switch from one to the other with byteswapping. Probably one of the reasons why this format is pretty much out of fashion these days ... cheers, Gerd _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
next prev parent reply other threads:[~2017-04-26 5:53 UTC|newest] Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-24 6:25 [PATCH 0/6] drm: tackle byteorder issues, take two Gerd Hoffmann 2017-04-24 6:25 ` [PATCH 1/6] drm: fourcc byteorder: drop DRM_FORMAT_BIG_ENDIAN Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-24 6:25 ` [PATCH 2/6] drm: fourcc byteorder: add DRM_FORMAT_CPU_* Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-24 6:25 ` [PATCH 3/6] drm: fourcc byteorder: add bigendian support to drm_mode_legacy_fb_format Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-25 3:18 ` Michel Dänzer 2017-04-25 3:18 ` Michel Dänzer 2017-04-25 9:52 ` Ville Syrjälä 2017-04-26 2:00 ` Michel Dänzer 2017-04-26 2:00 ` Michel Dänzer 2017-04-26 14:30 ` Ville Syrjälä 2017-04-26 14:30 ` Ville Syrjälä 2017-04-26 5:53 ` Gerd Hoffmann [this message] 2017-04-26 5:53 ` Gerd Hoffmann 2017-04-26 9:21 ` Michel Dänzer 2017-04-26 9:21 ` Michel Dänzer 2017-04-26 12:11 ` Gerd Hoffmann 2017-04-26 12:11 ` Gerd Hoffmann 2017-04-27 0:52 ` Michel Dänzer 2017-04-27 0:52 ` Michel Dänzer 2017-04-27 6:45 ` Gerd Hoffmann 2017-04-27 6:45 ` Gerd Hoffmann 2017-04-27 7:02 ` Michel Dänzer 2017-04-28 10:02 ` Gerd Hoffmann 2017-04-28 10:02 ` Gerd Hoffmann 2017-04-26 13:28 ` Eric Engestrom 2017-04-26 13:28 ` Eric Engestrom 2017-04-26 13:57 ` Gerd Hoffmann 2017-04-26 13:57 ` Gerd Hoffmann 2017-04-24 6:25 ` [PATCH 4/6] drm: fourcc byteorder: adapt bochs-drm to drm_mode_legacy_fb_format update Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-24 6:25 ` [PATCH 5/6] drm: fourcc byteorder: adapt virtio " Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann 2017-04-24 6:25 ` [PATCH 6/6] drm: fourcc byteorder: virtio restrict to XRGB8888 Gerd Hoffmann 2017-04-24 6:25 ` Gerd Hoffmann [not found] ` <20170424062532.26722-1-kraxel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> 2017-04-24 7:03 ` [PATCH 0/6] drm: tackle byteorder issues, take two Michel Dänzer [not found] ` <484f319e-c2b7-adc8-4ecf-537803cc2eee-otUistvHUpPR7s880joybQ@public.gmane.org> 2017-04-24 7:36 ` Gerd Hoffmann 2017-04-24 7:54 ` Michel Dänzer [not found] ` <f6555947-598f-0dfe-b15d-cda291778e8e-otUistvHUpPR7s880joybQ@public.gmane.org> 2017-04-24 14:26 ` Ville Syrjälä 2017-04-24 17:06 ` Daniel Stone [not found] ` <20170424142603.GX30290-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> 2017-04-24 17:28 ` Ville Syrjälä 2017-04-25 0:49 ` Michel Dänzer [not found] ` <65ba8ab7-d647-4b9e-1e8c-aa6e9b1ff996-otUistvHUpPR7s880joybQ@public.gmane.org> 2017-04-25 9:50 ` Ville Syrjälä
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