Re: [Intel-gfx] [PATCH v4 3/4] drm/shmem-helpers: Allocate wc pages on x86

[Thomas Zimmermann]

Hi

Am 23.07.21 um 09:36 schrieb Daniel Vetter:

The real fix is to get at the architecture-specific wc allocator, which is
currently not something that's exposed, but hidden within the dma api. I
think having this stick out like this is better than hiding it behind fake
generic code (like we do with drm_clflush, which defacto also only really
works on x86).

Also note that ttm has the exact same ifdef in its page allocator, but it
does fall back to using dma_alloc_coherent on other platforms.

Acked-by: Thomas Zimmermann <tzimmerm...@suse.de>

Best regards
Thomas

If this fixes a real problem and there's no full solution yet, let's take what we have. So if you can extract the essence of this comment into a TODO comment that tells how to fix the issue, fell free to add my

-Daniel

Best regard
Thomas

+
        shmem->pages = pages;
        return 0;
@@ -203,6 +212,11 @@ static void drm_gem_shmem_put_pages_locked(struct 
drm_gem_shmem_object *shmem)
        if (--shmem->pages_use_count > 0)
                return;
+#ifdef CONFIG_X86
+       if (shmem->map_wc)
+               set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
+#endif
+
        drm_gem_put_pages(obj, shmem->pages,
                          shmem->pages_mark_dirty_on_put,
                          shmem->pages_mark_accessed_on_put);

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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