On Fri, 26 Aug 2022 10:44:34 -0700, Rodrigo Vivi wrote:
Fixes: 7ba79a671568 ("drm/i915/guc/slpc: Gate Host RPS when SLPC is enabled") Cc: stable@vger.kernel.org # v5.15+ Cc: Ashutosh Dixit ashutosh.dixit@intel.com Tested-by: Sushma Venkatesh Reddy sushma.venkatesh.reddy@intel.com Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com
drivers/gpu/drm/i915/gt/intel_llc.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_llc.c b/drivers/gpu/drm/i915/gt/intel_llc.c index 14fe65812e42..2677d62573d9 100644 --- a/drivers/gpu/drm/i915/gt/intel_llc.c +++ b/drivers/gpu/drm/i915/gt/intel_llc.c @@ -49,13 +49,28 @@ static unsigned int cpu_max_MHz(void) static bool get_ia_constants(struct intel_llc *llc, struct ia_constants *consts) {
struct intel_guc_slpc *slpc = &llc_to_gt(llc)->uc.guc.slpc; struct drm_i915_private *i915 = llc_to_gt(llc)->i915; struct intel_rps *rps = &llc_to_gt(llc)->rps;
if (!HAS_LLC(i915) || IS_DGFX(i915)) return false;
- if (rps->max_freq <= rps->min_freq)
- if (intel_uc_uses_guc_slpc(&llc_to_gt(llc)->uc)) {
consts->min_gpu_freq = slpc->min_freq;consts->max_gpu_freq = slpc->rp0_freq;- } else {
consts->min_gpu_freq = rps->min_freq;consts->max_gpu_freq = rps->max_freq;- }
- if (GRAPHICS_VER(i915) >= 9) {
/* Convert GT frequency to 50 HZ units */consts->min_gpu_freq /= GEN9_FREQ_SCALER;consts->max_gpu_freq /= GEN9_FREQ_SCALER;- }
- if (consts->max_gpu_freq <= consts->min_gpu_freq) return false;
Hi Rodrigo, sorry, I missed this check previously too and the code is now equivalent to the previous code.
But now, looking at the code in gen6_update_ring_freq, I am wondering if we should return true in this case (i.e. remove the check) and we had a bug in the previous code? Because if we return false, gen6_update_ring_freq will skip the PCODE programming if 'max_gpu_freq == min_gpu_freq', but why should we skip the PCODE programming if 'max_gpu_freq == min_gpu_freq'? The case of 'max_gpu_freq < min_gpu_freq' is fine since the loop in gen6_update_ring_freq is not entered in that case.
Thanks. -- Ashutosh