On Tue, Oct 25, 2016 at 11:16:56AM -0700, Francisco Jerez wrote: > Kenneth Graunke <[email protected]> writes: > > > If the kernel advertises a new enough command parser version, then we > > can just assume that register writes will work and not bother executing > > commands on the GPU to test it. > > > > This should speed up context creation. > > > > From the command parser version history (i915_cmd_parser.c): > > > > * 1. Initial version. Checks batches and reports violations, but leaves > > * hardware parsing enabled (so does not allow new use cases). > > * 2. Allow access to the MI_PREDICATE_SRC0 and > > * MI_PREDICATE_SRC1 registers. > > > > Both of the things we check for were added before version 2, but > > 1 doesn't sound sufficient. The point is to skip work on modern > > kernels, so requiring version 2 will work. > > > > Signed-off-by: Kenneth Graunke <[email protected]> > > --- > > src/mesa/drivers/dri/i965/intel_extensions.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c > > b/src/mesa/drivers/dri/i965/intel_extensions.c > > index 66079b5..2a5a3b7 100644 > > --- a/src/mesa/drivers/dri/i965/intel_extensions.c > > +++ b/src/mesa/drivers/dri/i965/intel_extensions.c > > @@ -46,6 +46,10 @@ can_do_pipelined_register_writes(struct brw_context *brw) > > if (brw->gen != 7) > > return true; > > > > + /* No need to execute commands to check if the kernel advertises it. */ > > + if (brw->screen->cmd_parser_version >= 2) > > + return true; > > + > > static int result = -1; > > if (result != -1) > > return result; > > @@ -106,6 +110,10 @@ can_write_oacontrol(struct brw_context *brw) > > if (brw->gen < 6 || brw->gen >= 8) > > return false; > > > > + /* No need to execute commands to check if the kernel advertises it. */ > > + if (brw->screen->cmd_parser_version >= 2) > > + return true; > > + > > I'm not sure this gives you any guarantees that the command parser is > going to be active? Has the command parser been enabled by default on > all kernel versions exposing cmd_parser_version >= 2? Wouldn't this > break things if the command parser is disabled in the kernel command > line? [Currently it would just cause some extensions to be disabled]
We have the stance that touching any module option is an unsupported configuration, don't do that (and we'll ingore bug reports). Either way, the kernel reports 0 when the cmd parser is disabled. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
