Re: [igt-dev] [PATCH i-g-t 4/9] lib/igt_fb: Add checks on i915 for i915-specific tiled buffer allocation

Paul Kocialkowski
2018-12-13T13:29:35Z

Hi,

On Mon, 2018-12-10 at 18:30 +0200, Ville Syrjälä wrote:
> On Thu, Dec 06, 2018 at 03:11:27PM +0100, Paul Kocialkowski wrote:
> > The code path for allocating tiled buffers has a few i915-specific bits
> > without checks for the i915 driver. Add these missing checks.
>
> The else branch also has a bit of i915 specifics in it:
>
> void igt_get_fb_tile_size(int fd, uint64_t tiling, int fb_bpp,
> unsigned *width_ret, unsigned *height_ret)
> {
> switch (tiling) {
> case LOCAL_DRM_FORMAT_MOD_NONE:
> *width_ret = 64;
> *height_ret = 1;
> break;
>
> But I'm not sure if there is hardware that wouldn't be happy
> with 64 byte stride alignment.

Right, that wasn't causing any problem so I kept it untouched.

We could totally change that to align to a lower value (I think we need
at least 4 bytes for stride alignment to make pixman happy with using
the buffer).

If you think that change is necessary, I could make it a follow-up
patch or integrate it in the next revision.

Cheers,

Paul

> > For the map_bo function, initially define the return pointer to
> > MAP_FAILED and assert that it's not MAP_FAILED when no mapping function
> > was found, in order to provide an understandable error when it occurs.
> >
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > ---
> > lib/igt_fb.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/igt_fb.c b/lib/igt_fb.c
> > index f2e6c89f..ccdf07d0 100644
> > --- a/lib/igt_fb.c
> > +++ b/lib/igt_fb.c
> > @@ -298,6 +298,7 @@ static uint32_t calc_plane_stride(struct igt_fb *fb, int plane)
> > (fb->plane_bpp[plane] / 8);
> >
> > if (fb->tiling != LOCAL_DRM_FORMAT_MOD_NONE &&
> > + is_i915_device(fb->fd) &&
> > intel_gen(intel_get_drm_devid(fb->fd)) <= 3) {
> > uint32_t stride;
> >
> > @@ -326,6 +327,7 @@ static uint32_t calc_plane_stride(struct igt_fb *fb, int plane)
> > static uint64_t calc_plane_size(struct igt_fb *fb, int plane)
> > {
> > if (fb->tiling != LOCAL_DRM_FORMAT_MOD_NONE &&
> > + is_i915_device(fb->fd) &&
> > intel_gen(intel_get_drm_devid(fb->fd)) <= 3) {
> > uint64_t min_size = (uint64_t) fb->strides[plane] *
> > fb->plane_height[plane];
> > @@ -1466,7 +1468,7 @@ static void destroy_cairo_surface__gtt(void *arg)
> >
> > static void *map_bo(int fd, struct igt_fb *fb)
> > {
> > - void *ptr;
> > + void *ptr = MAP_FAILED;
> >
> > if (is_i915_device(fd))
> > gem_set_domain(fd, fb->gem_handle,
> > @@ -1475,9 +1477,11 @@ static void *map_bo(int fd, struct igt_fb *fb)
> > if (fb->is_dumb)
> > ptr = kmstest_dumb_map_buffer(fd, fb->gem_handle, fb->size,
> > PROT_READ | PROT_WRITE);
> > - else
> > + else if (is_i915_device(fd))
> > ptr = gem_mmap__gtt(fd, fb->gem_handle, fb->size,
> > PROT_READ | PROT_WRITE);
> > + else
> > + igt_assert(ptr != MAP_FAILED);
>
> igt_assert(0)?
>
> >
> > return ptr;
> > }
> > --
> > 2.19.2
--
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering