diff options
author | Chris Wilson <chris@chris-wilson.co.uk> | 2018-09-03 16:23:04 +0100 |
---|---|---|
committer | Chris Wilson <chris@chris-wilson.co.uk> | 2018-09-03 17:55:59 +0100 |
commit | d6acae363e63d655ba892c139ba14f24206462c0 (patch) | |
tree | f92ecf6401109a9f619448ded1dd5f49e5567e8a /drivers/gpu/drm/i915/intel_engine_cs.c | |
parent | a0e731f4e26c4d774e71f9e69fff3e88d49dd34f (diff) |
drm/i915: Use a cached mapping for the physical HWS
Older gen use a physical address for the hardware status page, for which
we use cache-coherent writes. As the writes are into the cpu cache, we use
a normal WB mapped page to read the HWS, used for our seqno tracking.
Anecdotally, I observed lost breadcrumbs writes into the HWS on i965gm,
which so far have not reoccurred with this patch. How reliable that
evidence is remains to be seen.
v2: Explicitly pass the expected physical address to the hw
v3: Also remember the wild writes we once had for HWS above 4G.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180903152304.31589-2-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/intel_engine_cs.c')
-rw-r--r-- | drivers/gpu/drm/i915/intel_engine_cs.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index 292eae19fce2..10cd051ba29e 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -532,11 +532,11 @@ void intel_engine_cleanup_scratch(struct intel_engine_cs *engine) static void cleanup_status_page(struct intel_engine_cs *engine) { - struct drm_dma_handle *dmah; + if (HWS_NEEDS_PHYSICAL(engine->i915)) { + void *addr = fetch_and_zero(&engine->status_page.page_addr); - dmah = fetch_and_zero(&engine->i915->status_page_dmah); - if (dmah) - drm_pci_free(&engine->i915->drm, dmah); + __free_page(virt_to_page(addr)); + } i915_vma_unpin_and_release(&engine->status_page.vma, I915_VMA_RELEASE_MAP); @@ -605,17 +605,18 @@ err: static int init_phys_status_page(struct intel_engine_cs *engine) { - struct drm_i915_private *dev_priv = engine->i915; - - GEM_BUG_ON(engine->id != RCS); + struct page *page; - dev_priv->status_page_dmah = - drm_pci_alloc(&dev_priv->drm, PAGE_SIZE, PAGE_SIZE); - if (!dev_priv->status_page_dmah) + /* + * Though the HWS register does support 36bit addresses, historically + * we have had hangs and corruption reported due to wild writes if + * the HWS is placed above 4G. + */ + page = alloc_page(GFP_KERNEL | __GFP_DMA32 | __GFP_ZERO); + if (!page) return -ENOMEM; - engine->status_page.page_addr = dev_priv->status_page_dmah->vaddr; - memset(engine->status_page.page_addr, 0, PAGE_SIZE); + engine->status_page.page_addr = page_address(page); return 0; } |