On Mon, Dec 17, 2012 at 04:46:17PM +0200, Ville Syrj?l? wrote: > On Mon, Dec 17, 2012 at 02:43:03PM +0100, Daniel Vetter wrote: > > On Mon, Dec 17, 2012 at 01:33:01PM +0000, Chris Wilson wrote: > > > On Sun, 16 Dec 2012 22:46:00 +0000, Chris Wilson <chris at chris-wilson.co.uk> wrote: > > > > @@ -1087,6 +1087,9 @@ i915_error_first_batchbuffer(struct drm_i915_private *dev_priv, > > > > if (!ring->get_seqno) > > > > return NULL; > > > > > > > > + if (HAS_BROKEN_CS_TLB(dev_priv->dev)) > > > > + return i915_error_object_create(dev_priv, ring->private); > > > > > > Hmm, this is complicated by userspace opting out of the CS w/a, and > > > imposes quite a burden upon our simple seq interface. > > > > Right, I've written this without userspace being able to opt out in mind > > ... for the seq -ENOMEM, I guess it's just time to bite the bullet. Loads > > of the error_states for the ilk fallout couldn't be dumped (but could be > > captured) by bug reporters already :( > > Assuming you're talking about debugfs error_state returning -ENOMEM due > to seq_file's massive kmalloc(), I had a couple of ideas for fixing it > in seq_file itself. > > 1) just use vmalloc() > > 2) use multiple pages instead of one big allocation > > seq_printf() { > try to print the line > if not enough space { > mark the end of valid data in current page > allocate a new page > print again > } > } > > And adjust seq_read()/seq_lseek accordingly. > > Of course then you can't print anything > PAGE_SIZE, > but that seems unlikely anyway, and if really needed > it could try to allocate something larger than a page > when needed. Afaik that's pretty much what the real seq_file interface does, we just need to port the error state dump code over from the simple_seq_file to the real one. But since seq_file is designed for more regular stuff, this will be a slight pain, so I've tried to avoid this ... It sounds like I'm running low on excuses ;-) -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch