From 7978b9cfa59133a34aaad420e447c2a29d5c6152 Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Wed, 6 Jan 2010 12:00:02 +1000 Subject: [PATCH] drm/nv50: prevent a possible ctxprog hang The below is mainly an educated guess at what's going on, docs would sure be handy... NVIDIA? :P It appears it's possible for a ctxprog to run even while a GPU exception is pending. The GF8 and up ctxprogs appear to have a small snippet of code which detects this, and stalls the ctxprog until it's been handled, which essentially looks like: if (r2 & 0x00008000) { r0 |= 0x80000000; while (r0 & 0x80000000) {} } I don't know of any way that flag would get cleared unless the driver intervenes (and indeed, in the cases I've seen the hang, nothing steps in to automagically clear it for us). This patch causes the driver to clear the flag during the PGRAPH IRQ handler. Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_irq.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/nouveau/nouveau_irq.c b/drivers/gpu/drm/nouveau/nouveau_irq.c index 370c72c..919a619 100644 --- a/drivers/gpu/drm/nouveau/nouveau_irq.c +++ b/drivers/gpu/drm/nouveau/nouveau_irq.c @@ -635,6 +635,7 @@ nv50_pgraph_irq_handler(struct drm_device *dev) if ((nv_rd32(dev, 0x400500) & isb) != isb) nv_wr32(dev, 0x400500, nv_rd32(dev, 0x400500) | isb); + nv_wr32(dev, 0x400824, nv_rd32(dev, 0x400824) & ~(1 << 31)); } nv_wr32(dev, NV03_PMC_INTR_0, NV_PMC_INTR_0_PGRAPH_PENDING); -- 2.7.4