On Mon, 20 Jun 2016 09:45:26 -0400 Rob Clark <robdcl...@gmail.com> wrote:
> On Mon, Jun 20, 2016 at 8:37 AM, Pekka Paalanen <ppaala...@gmail.com> wrote: > > On Fri, 17 Jun 2016 11:44:34 -0400 > > Rob Clark <robdcl...@gmail.com> wrote: > > > >> On Fri, Jun 17, 2016 at 9:31 AM, Pekka Paalanen <ppaala...@gmail.com> > >> wrote: > >> > On Fri, 17 Jun 2016 08:26:04 -0400 > >> > Rob Clark <robdcl...@gmail.com> wrote: > >> > > >> >> On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen <ppaala...@gmail.com> > >> >> wrote: > >> >> > On Thu, 16 Jun 2016 10:40:51 -0400 > >> >> > Rob Clark <robdcl...@gmail.com> wrote: > >> >> > > >> >> >> So, if we wanted to extend this to support the fourcc-modifiers that > >> >> >> we have on the kernel side for compressed/tiled/etc formats, what > >> >> >> would be the right approach? > >> >> >> > >> >> >> A new version of the existing extension or a new > >> >> >> EGL_EXT_image_dma_buf_import2 extension, or ?? > >> >> > > >> >> > Hi Rob, > >> >> > > >> >> > there are actually several things it might be nice to add: > >> >> > > >> >> > - a fourth plane, to match what DRM AddFB2 supports > >> >> > > >> >> > - the 64-bit fb modifiers > >> >> > > >> >> > - queries for which pixel formats are supported by EGL, so a display > >> >> > server can tell the applications that before the application goes > >> >> > and > >> >> > tries with a random bunch of them, shooting in the dark > >> >> > > >> >> > - queries for which modifiers are supported for each pixel format, > >> >> > ditto > >> >> > > >> >> > I discussed these with Emil in the past, and it seems an appropriate > >> >> > approach might be the following. > >> >> > > >> >> > Adding the 4th plane can be done as revising the existing > >> >> > EGL_EXT_image_dma_buf_import extension. The plane count is tied to > >> >> > pixel formats (and modifiers?), so the user does not need to know > >> >> > specifically whether the EGL implementation could handle a 4th plane > >> >> > or > >> >> > not. It is implied by the pixel format. > >> >> > > >> >> > Adding the fb modifiers needs to be a new extension, so that users can > >> >> > tell if they are supported or not. This is to avoid the following > >> >> > false > >> >> > failure: if user assumes modifiers are always supported, it will > >> >> > (may?) > >> >> > provide zero modifiers explicitly. If EGL implementation does not > >> >> > handle modifiers this would be rejected as unrecognized attributes, > >> >> > while if the zero modifiers were not given explicitly, everything > >> >> > would > >> >> > just work. > >> >> > >> >> hmm, if we design it as "not passing modifier" == "zero modifier", and > >> >> "never explicitly pass a zero modifier" then modifiers could be added > >> >> without a new extension. Although I agree that queries would need a > >> >> new extension.. so perhaps not worth being clever. > >> > > >> > Indeed. > >> > > >> >> > The queries obviously(?) need a new extension. It might make sense > >> >> > to bundle both modifier support and the queries in the same new > >> >> > extension. > >> >> > > >> >> > We have some rough old WIP code at > >> >> > https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers > >> >> > https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410 > >> >> > > >> >> > > >> >> >> On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey <tom.cook...@arm.com> > >> >> >> wrote: > >> >> >> > Hi All, > >> >> >> > > >> >> >> > The final spec has had enum values assigned and been published on > >> >> >> > Khronos: > >> >> >> > > >> >> >> > http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_import.txt > >> >> >> > > >> >> >> > Thanks to all who've provided input. > >> >> > > >> >> > May I also pull your attention to a detail with the existing spec and > >> >> > Mesa behaviour I am asking about in > >> >> > https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html > >> >> > "What is EGL_EXT_image_dma_buf_import image orientation as a GL > >> >> > texture?" > >> >> > Doing a dmabuf import seems to imply an y-flip AFAICT. > >> >> > >> >> I would have expected that *any* egl external image (dma-buf or > >> >> otherwise) should have native orientation rather than gl orientation. > >> >> It's somewhat useless otherwise. > >> > > >> > In that case importing dmabuf works differently than importing a > >> > wl_buffer (wl_drm), because for the latter, the y-invert flag is > >> > returned such that the orientation will match GL. And the direct > >> > scanout path goes through GBM since you have to import a wl_buffer, and > >> > I haven't looked what GBM does wrt. y-flip if anything. > >> > > >> >> I didn't read it carefully yet (would need caffeine first ;-)) but > >> >> EGL_KHR_image_base does say "This extension defines a new EGL resource > >> >> type that is suitable for sharing 2D arrays of image data between > >> >> client APIs" which to me implies native orientation. So that just > >> >> sounds like a mesa bug somehow? > >> > > >> > That specific sentence implies nothing about orientation to me. > >> > Furthermore, the paragraph continues: > >> > > >> > "Although the intended purpose is sharing 2D image data, the > >> > underlying interface makes no assumptions about the format or > >> > purpose of the resource being shared, leaving those decisions > >> > to the application and associated client APIs." > >> > > >> > Might "format" include orientation? > >> > > >> > How does "native orientation" connect with "GL texture coordinates"? > >> > The latter have explicitly defined orientation and origin. For use in > >> > GL, the right way up image is having the origin in the bottom-left > >> > corner. An image right way up is an image right way up, regardless > >> > which corner is the origin. The problem comes when you start using > >> > coordinates. > >> > > >> >> Do you just get that w/ i965? I know some linaro folks have been > >> >> using this extension to import buffers from video decoder with > >> >> freedreno/gallium and no one mentioned the video being upside down. > >> > > >> > Intel, yes, but since this happens *only* for the GL import path and > >> > direct scanout is fine without y-flipping, I bet people just flipped y > >> > and did not think twice, if there even was a problem. I just have a > >> > habit of asking "why". ;-) > >> > >> well, if possible, try with one of the gallium drivers? > >> > >> I'm honestly not 100% sure what it is supposed to be according to the > >> spec, but I do know some of the linaro folks were doing v4l2dec -> > >> glimagesink with dmabuf with both mali (I think some ST platform?) and > >> freedreno (snapdragon db410c), and no one complained to me that the > >> video was upside down for one or the other. So I guess at least > >> gallium and mali are doing the same thing. No idea if that is the > >> same thing that i965 does. > > > > Hi, > > > > Quentin did some tests for me, and the results are... not what I would > > have expected: > > https://phabricator.freedesktop.org/T7475#88454 > > > > RadeonSI works like Intel, but Nouveau does the opposite. I think the > > Nouveau way is correct by the spec, which makes everyone else (intel, > > radeonsi, weston-simple-dmabuf-v4l) get it wrong. Unfortunately, two > > wrongs make a right, so when weston-simple-dmabuf-v4l hardcodes Y_INVERT > > as set, it'll come out the right way on intel and radeon. > > oh, wow.. that seems quite odd that two different gallium drivers have > different results, since I'd have expected this to be completely > handled by mesa/st.. now I'm somewhat curious. Hi, after a head-scratching session on #dri-devel and a little bit on #wayland too, I'm ready to punt that off as a bad test. It is quite possible the machine running nouveau had a webcam that really produces upside-down images. weston-simple-dmabuf-v4l does not understand that. Apparently mpv OTOH does. How, maybe there is an answer in V4L2 API, but I haven't looked it up yet. If we look at the Vivid tests, the results are consistent and expected. All intel, nouveau and radeon work the same way. > > And it is wrong for weston-simple-dmabuf-v4l to set Y_INVERT, that I > > believe is clear. It is only there because of the "oops, it's > > upside-down" syndrome, AFAIK. > > > >> > After all, using GL with windows and FBOs and stuff you very often find > >> > yourself upside down, and I suspect people have got the habit of just > >> > flipping it if it does not look right the first time. See e.g. the > >> > row-order of data going into glTexImage2D... > >> > > >> > If the answer is "oops, well, dmabuf import is semantically y-flipping > >> > when it should not, but we cannot fix it because that would break > >> > everyone", I would be happy with that. I just want confirmation before > >> > flipping the flip flag. :-) > > > > So many bugs that accidentally counter each other... Seems like we can conclude this by saying that a dmabuf imported via EGL as a GL texture will have the origin at top-left, instead of what the GL spec says. Thanks, pq
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