[PATCH 2/3] drm/panthor: Make sure the tiler initial/max chunks are consistent

[Boris Brezillon]

On Thu, 25 Apr 2024 11:43:39 +0100
Steven Price <steven.price at arm.com> wrote:

> On 25/04/2024 10:28, Steven Price wrote:
> > On 25/04/2024 08:18, Boris Brezillon wrote:  
> >> It doesn't make sense to have a maximum number of chunks smaller than
> >> the initial number of chunks attached to the context.
> >>
> >> Fix the uAPI header to reflect the new constraint, and mention the
> >> undocumented "initial_chunk_count > 0" constraint while at it.
> >>
> >> Fixes: 9cca48fa4f89 ("drm/panthor: Add the heap logical block")
> >> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>  
> > 
> > Reviewed-by: Steven Price <steven.price at arm.com>  
> 
> Ok, I'll take that back... I've rebased (and fixed up all the out of
> tree patches) and this doesn't work when I actually test it!
> 
> >   
> >> ---
> >>  drivers/gpu/drm/panthor/panthor_heap.c | 3 +++
> >>  include/uapi/drm/panthor_drm.h         | 8 ++++++--
> >>  2 files changed, 9 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c
> >> index 143fa35f2e74..8728c9bb76e4 100644
> >> --- a/drivers/gpu/drm/panthor/panthor_heap.c
> >> +++ b/drivers/gpu/drm/panthor/panthor_heap.c
> >> @@ -281,6 +281,9 @@ int panthor_heap_create(struct panthor_heap_pool *pool,
> >>  	if (initial_chunk_count == 0)
> >>  		return -EINVAL;
> >>  
> >> +	if (initial_chunk_count < max_chunks)  
> 
> This should be initial_chunk_count > max_chunks. Otherwise you're
> requiring the initial chunk count to be equal *or greater* than the max
> chunks which makes no sense!

Damn it, here's what happens when you think your changes are too
trivial to be wrong...

But I swear I would have tested the whole thing before pushing to
drm-misc. :P