Messages in this thread | | | Subject | Re: [PATCH 3/3] drm: omapdrm: Do no allocate non-scanout GEMs through DMM/TILER | From | Ivaylo Dimitrov <> | Date | Fri, 2 Sep 2022 17:13:34 +0300 |
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On 30.08.22 г. 21:23 ч., Tomi Valkeinen wrote: > On 30/08/2022 21:08, Ivaylo Dimitrov wrote: > >>>> flags &= ~OMAP_BO_TILED_MASK; >>>> flags |= 0x00000008; >>>> flags |= OMAP_BO_WC; >>>> >>>> bo = omap_bo_new(dev, size, flags); >>>> >>>> As you can see we use 0x00000008 (OMAP_BO_MEM_CONTIG) unconditionally. >>>> This was a hack added since even non-scanout buffers sometimes need >>>> to be contiguous (video decoder surfaces), but we had no way back >> >> Hmm, why would video decoder need linear memory? No MMU? > > Not sure about this case, but many/most IPs don't have MMU. E.g. CSI-2 > or parallel capture. > >>>> If you tell me what the code should look like, I can rebuild the >>>> lib and post a copy. >>>> >>>> Long term, I'd like to start using DMA-BUF Heaps for CMA memory >>>> allocations in gralloc and elsewhere, then drop out the DMM/TILER >>>> support from OMAPDRM, since it never really belonged there in >>>> the first place (being a IOMMU unrelated to the display/GPU). >>>> >> >> Umm, how will we rotate scanout buffers then? > > Didn't we discuss this earlier in this thread. Or some other thread. > Related to VRFB... I'm not sure =). >
Yeah, I think so. VRFB is still on my list though, along with TE support for droid4 :).
> Anyway, neither VRFB nor DMM/TILER are part of the DSS. They're part of > the memory subsystem. They can be used without DSS being in the setup. > Thus the code for VRFB and DMM/TILER should not be in the DSS driver. >
Makes sense.
> The DSS driver should still, of course, support DMM/TILER (and maybe > VRFB some day) in the "use" sense, i.e. so that DSS can use the > DMM/TILER provided from another driver. >
Ah, this is what I was missing all the time, for some reason I was left with the impression that userland will have to know about those details. Now it is clear.
> But how exactly that's to be implemented, I don't know. >
Seems Andrew has an idea.
Ivo
> Tomi
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