On Fri, Feb 21, 2014 at 05:31:59PM +0200, mika.kuoppala@xxxxxxxxx wrote: > From: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> > > Sometimes generic driver code gets forcewake explicitly by > gen6_gt_force_wake_get(), which check forcewake_count before accessing > hardware. However the register access with gen8_write function access > low level hw accessors directly, ignoring the forcewake_count. This > leads to nested forcewake get from hardware, in ring init and possibly > elsewhere, causing forcewake ack clear errors and/or hangs. > > Fix this by checking the forcewake count also in gen8_write > > v2: Read side doesn't care about shadowed registers, > Remove __needs_put funkiness from gen8_write. (Ville) > Improved commit message. > > References: https://bugs.freedesktop.org/show_bug.cgi?id=74007 > Cc: Ben Widawsky <benjamin.widawsky@xxxxxxxxx> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> > Reviewed-by: Ben Widawsky <ben@xxxxxxxxxxxx> For those concerned with the performance implication of the extra if (if anyone at all cares, it's Chris) - I suppose we could also just add the lock to gen6_gt_force_wake_get/put. [snip] -- Ben Widawsky, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
