On Fri, Mar 24, 2017 at 04:35:38PM +0000, Chris Wilson wrote: > Note all of our target platforms have clflush. For those without, just > assume the status page is sufficiently coherent that we do not need our > paranoia. > > Reported-by: Ville Syrjälä <[email protected]> > Fixes: 14a6bbf9e535 ("drm/i915: Replace irq_seqno_barrier on hws write with a > clflush") > Signed-off-by: Chris Wilson <[email protected]> > Cc: Mika Kuoppala <[email protected]> > Cc: Ville Syrjälä <[email protected]> > --- > drivers/gpu/drm/i915/intel_ringbuffer.h | 22 +++++++++++++++------- > 1 file changed, 15 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h > b/drivers/gpu/drm/i915/intel_ringbuffer.h > index 2ecb41788fb6..b5ce6692ed8a 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.h > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h > @@ -454,14 +454,22 @@ intel_read_status_page(struct intel_engine_cs *engine, > int reg) > } > > static inline void > -intel_write_status_page(struct intel_engine_cs *engine, > - int reg, u32 value) > +intel_write_status_page(struct intel_engine_cs *engine, int reg, u32 value) > { > - mb(); > - clflush(&engine->status_page.page_addr[reg]); > - engine->status_page.page_addr[reg] = value; > - clflush(&engine->status_page.page_addr[reg]); > - mb(); > + /* Writing into the status page should be done sparingly. Since > + * we do when we are uncertain of the device state, we take a bit > + * if extra paranoia to try and ensure that the HWS takes the value > + * we give and that it doesn't end up trapped inside the CPU! > + */ > + if (static_cpu_has(X86_FEATURE_CLFLUSH)) { > + mb(); > + clflush(&engine->status_page.page_addr[reg]); > + engine->status_page.page_addr[reg] = value; > + clflush(&engine->status_page.page_addr[reg]); > + mb(); > + } else { > + WRITE_ONCE(engine->status_page.page_addr[reg], value); > + }
Fixes the illegal opcode explosion. Tested-by: Ville Syrjälä <[email protected]> Unfortunately the GPU still dies as soon as I fire up glxgears. 4.9 seems to be working just fine, so looks like a kernel regression. > } > > /* > -- > 2.11.0 -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
