Re: [PATCH 06/11] drm/radeon: stop using TTM_MEMTYPE_FLAG_MAPPABLE

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Jul 22, 2020 at 1:50 PM Christian König
<christian.koenig@amd.com> wrote:
>
> Am 22.07.20 um 13:42 schrieb Daniel Vetter:
> > On Wed, Jul 22, 2020 at 1:13 PM Christian König
> > <christian.koenig@amd.com> wrote:
> >> Am 22.07.20 um 07:34 schrieb Daniel Vetter:
> >>> On Tue, Jul 21, 2020 at 4:46 PM Christian König
> >>> <ckoenig.leichtzumerken@gmail.com> wrote:
> >>>> Am 21.07.20 um 11:24 schrieb daniel@ffwll.ch:
> >>>>> On Tue, Jul 21, 2020 at 09:32:40AM +0200, Christian König wrote:
> >>>>>> The driver doesn't expose any not-mapable memory resources.
> >>>>>>
> >>>>>> Signed-off-by: Christian König <christian.koenig@amd.com>
> >>>>>> ---
> >>>>>>     drivers/gpu/drm/radeon/radeon_ttm.c | 13 ++++---------
> >>>>>>     1 file changed, 4 insertions(+), 9 deletions(-)
> >>>>>>
> >>>>>> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
> >>>>>> index 54af06df865b..b474781a0920 100644
> >>>>>> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
> >>>>>> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
> >>>>>> @@ -76,7 +76,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
> >>>>>>        switch (type) {
> >>>>>>        case TTM_PL_SYSTEM:
> >>>>>>                /* System memory */
> >>>>>> -            man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
> >>>>>> +            man->flags = 0;
> >>>>>>                man->available_caching = TTM_PL_MASK_CACHING;
> >>>>>>                man->default_caching = TTM_PL_FLAG_CACHED;
> >>>>>>                break;
> >>>>>> @@ -84,7 +84,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
> >>>>>>                man->func = &ttm_bo_manager_func;
> >>>>>>                man->available_caching = TTM_PL_MASK_CACHING;
> >>>>>>                man->default_caching = TTM_PL_FLAG_CACHED;
> >>>>>> -            man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
> >>>>>> +            man->flags = 0;
> >>>>>>     #if IS_ENABLED(CONFIG_AGP)
> >>>>>>                if (rdev->flags & RADEON_IS_AGP) {
> >>>>>>                        if (!rdev->ddev->agp) {
> >>>>>> @@ -92,8 +92,6 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
> >>>>>>                                          (unsigned)type);
> >>>>>>                                return -EINVAL;
> >>>>>>                        }
> >>>>>> -                    if (!rdev->ddev->agp->cant_use_aperture)
> >>>>>> -                            man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
> >>>>> There is a bunch of agp drivers (alpha, ppc, that kind of stuff) with this
> >>>>> flag set. And radeon.ko did at least once work on these. And your patch to
> >>>>> disable agp only changes the default, it doesn't rip out the code.
> >>>> The key pint is that the flags for AGP are the same as the one for the
> >>>> PCIe path. So no functional change at all :)
> >>> I misread the code somehow, I didn't spot the unconditional setting of
> >>> FLAG_MAPPABLE for all TTM_PL_TT, irrespective of agp or not, somehow
> >>> thought that's another case.
> >>>
> >>> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> >> And for the amdgpu patch? Otherwise I just ping Alex for an rb.
> > See my question over there, I'm not seeing how the code prevents mmap
> > for AMDGPU_PL_* domains after your patch. Once that's cleared up happy
> > to r-b that one and the final one too.
>
> I already replied, sounds like you never got that.

I got it, but I suck at reading mailing lists.

> Anyway see the switch just below the two lines I removed:
> >         switch (mem->mem_type) {
> >         case TTM_PL_SYSTEM:
> ....
> >         case TTM_PL_TT:
> ...
> >         case TTM_PL_VRAM:
> ...
> >         default:
> >                 return -EINVAL;
> >         }
>
> So again, no functional change at all.

Indeed, I score another point for being blind. r-b: also on the amdgpu
and final cleanup patch.
-Daniel

>
> Cheers,
> Christian.
>
> > -Daniel
> >
> >> Thanks,
> >> Christian.
> >>
> >>>> The real handling of cant_use_aperture is in radeon_ttm_io_mem_reserve().
> >>>>
> >>>> Christian.
> >>>>
> >>>>> So not sure your assumption here is correct.
> >>>>> -Daniel
> >>>>>
> >>>>>>                        man->available_caching = TTM_PL_FLAG_UNCACHED |
> >>>>>>                                                 TTM_PL_FLAG_WC;
> >>>>>>                        man->default_caching = TTM_PL_FLAG_WC;
> >>>>>> @@ -103,8 +101,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
> >>>>>>        case TTM_PL_VRAM:
> >>>>>>                /* "On-card" video ram */
> >>>>>>                man->func = &ttm_bo_manager_func;
> >>>>>> -            man->flags = TTM_MEMTYPE_FLAG_FIXED |
> >>>>>> -                         TTM_MEMTYPE_FLAG_MAPPABLE;
> >>>>>> +            man->flags = TTM_MEMTYPE_FLAG_FIXED;
> >>>>>>                man->available_caching = TTM_PL_FLAG_UNCACHED | TTM_PL_FLAG_WC;
> >>>>>>                man->default_caching = TTM_PL_FLAG_WC;
> >>>>>>                break;
> >>>>>> @@ -394,7 +391,6 @@ static int radeon_bo_move(struct ttm_buffer_object *bo, bool evict,
> >>>>>>
> >>>>>>     static int radeon_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
> >>>>>>     {
> >>>>>> -    struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
> >>>>>>        struct radeon_device *rdev = radeon_get_rdev(bdev);
> >>>>>>
> >>>>>>        mem->bus.addr = NULL;
> >>>>>> @@ -402,8 +398,7 @@ static int radeon_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_
> >>>>>>        mem->bus.size = mem->num_pages << PAGE_SHIFT;
> >>>>>>        mem->bus.base = 0;
> >>>>>>        mem->bus.is_iomem = false;
> >>>>>> -    if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
> >>>>>> -            return -EINVAL;
> >>>>>> +
> >>>>>>        switch (mem->mem_type) {
> >>>>>>        case TTM_PL_SYSTEM:
> >>>>>>                /* system memory */
> >>>>>> --
> >>>>>> 2.17.1
> >>>>>>
> >>>>>> _______________________________________________
> >>>>>> dri-devel mailing list
> >>>>>> dri-devel@lists.freedesktop.org
> >>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fdri-devel&amp;data=02%7C01%7Cchristian.koenig%40amd.com%7Cb10b1b6716484915990d08d82e3465f4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637310149874876539&amp;sdata=Ub8%2F0d13KkJdu7YAtFWpJtoVXuT8RrTewKSuBU6QnYo%3D&amp;reserved=0
> >
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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