[Intel-gfx] [PATCH 3/8] drm/i915/pcode: Extend pcode functions for multiple gt's

[Rodrigo Vivi]

On Thu, Apr 14, 2022 at 03:31:07PM -0700, Dixit, Ashutosh wrote:
> On Thu, 14 Apr 2022 06:28:57 -0700, Jani Nikula wrote:
> >
> > On Wed, 13 Apr 2022, Ashutosh Dixit <ashutosh.dixit at intel.com> wrote:
> > > Each gt contains an independent instance of pcode. Extend pcode functions
> > > to interface with pcode on different gt's. Previous (GT0) pcode read/write
> > > interfaces are preserved.
> >
> > The big problem here is that this hard couples display code to gt code,
> > while we're trying hard to go the opposite direction. It doesn't matter
> > that the existing interfaces are preserved as wrappers when it relies on
> > an intel_gt being available (via i915->gt0).

I don't believe there is a big problem in here...

please note the intel_pcode.h is keeping the abstraction for display

#define snb_pcode_write_timeout(i915, mbox, val, fast_timeout_us, slow_timeout_ms) \
        intel_gt_pcode_write_timeout(&(i915)->gt0, mbox, val, fast_timeout_us, slow_timeout_ms)

#define snb_pcode_write(i915, mbox, val) \
        snb_pcode_write_timeout(i915, mbox, val, 500, 0)

display only uses these macros that Ashutosh didn't touch.

> >
> > Note how 'git grep intel_gt -- drivers/gpu/drm/i915/display/' matches
> > only 1 line.

As well with the patches applied:

$ git log --oneline -1
1f58f1195478 (HEAD -> drm-tip) drm/i915/gt: Expose per-gt RPS defaults in sysfs

$ git grep intel_gt -- drivers/gpu/drm/i915/display/
drivers/gpu/drm/i915/display/intel_display.c:           intel_gt_set_wedged(to_gt(dev_priv));

>
> Hi Jani, would you have suggestions about how to do this (handle pcode on
> multiple gt's)? The thinking was this patch would be a straightforward way
> to avoid code duplication. Also:

Maybe it is just a matter of renaming the macros used by display
in intel_pcode.h to reflect that it should be used by display only?

Thanks,
Rodrigo.

>
> int intel_gt_probe_all() {
> 	...
>        /*
>         * We always have at least one primary GT on any device
>         * and it has been already initialized early during probe
>         * in i915_driver_probe()
>         */
>
> Thanks.