drm/i915/guc: Disable PL1 power limit when loading GuC firmware
On dGfx, the PL1 power limit being enabled and set to a low value results
in a low GPU operating freq. It also negates the freq raise operation which
is done before GuC firmware load. As a result GuC firmware load can time
out. Such timeouts were seen in the GL #8062 bug below (where the PL1 power
limit was enabled and set to a low value). Therefore disable the PL1 power
limit when allowed by HW when loading GuC firmware.
v2:
- Take mutex (to disallow writes to power1_max) across GuC reset/fw load
- Add hwm_power_max_restore to error return code path
v3 (Jani N):
- Add/remove explanatory comments
- Function renames
- Type corrections
- Locking annotation
v4:
- Don't hold the lock across GuC reset (Rodrigo)
- New locking scheme (suggested by Rodrigo)
- Eliminate rpm_get in power_max_disable/restore, not needed (Tvrtko)
v5:
- Fix uninitialized pl1en variable compile warning reported by kernel
build robot by creating new err_rps label
Link: https://gitlab.freedesktop.org/drm/intel/-/issues/8062
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230420164041.1428455-3-ashutosh.dixit@intel.com