[Intel-gfx] [PATCH] drm/i915/guc: Dump perf_limit_reasons for debug

[Dixit, Ashutosh]

On Mon, 26 Jun 2023 21:02:14 -0700, Belgaumkar, Vinay wrote:
>
>
> On 6/26/2023 8:17 PM, Dixit, Ashutosh wrote:
> > On Mon, 26 Jun 2023 19:12:18 -0700, Vinay Belgaumkar wrote:
> >> GuC load takes longer sometimes due to GT frequency not ramping up.
> >> Add perf_limit_reasons to the existing warn print to see if frequency
> >> is being throttled.
> >>
> >> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> >> ---
> >>   drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c | 2 ++
> >>   1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
> >> index 364d0d546ec8..73911536a8e7 100644
> >> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
> >> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
> >> @@ -254,6 +254,8 @@ static int guc_wait_ucode(struct intel_guc *guc)
> >>		guc_warn(guc, "excessive init time: %lldms! [freq = %dMHz, before = %dMHz, status = 0x%08X, count = %d, ret = %d]\n",
> >>			 delta_ms, intel_rps_read_actual_frequency(&uncore->gt->rps),
> >>			 before_freq, status, count, ret);
> >> +		guc_warn(guc, "perf limit reasons = 0x%08X\n",
> >> +			 intel_uncore_read(uncore, intel_gt_perf_limit_reasons_reg(gt)));
> > Maybe just add at the end of the previous guc_warn?
>
> Its already too long a line. If I try adding on the next line checkpatch
> complains about splitting double quotes.

In these cases of long quoted lines we generally ignore checkpatch. Because
perf limit reasons is part of the "excessive init time" message it should
be on the same line within the square brackets. So should not be
splitting double quotes.

Another idea would be something like this:

		guc_warn(guc, "excessive init time: %lldms! [freq = %dMHz, before = %dMHz, status = 0x%08X]\n",
			 delta_ms, intel_rps_read_actual_frequency(&uncore->gt->rps),
			 before_freq, status);
		guc_warn(guc, "excessive init time: [count = %d, ret = %d, perf limit reasons = 0x%08X]\n",
			 count, ret, intel_uncore_read(uncore, intel_gt_perf_limit_reasons_reg(gt)));

Thanks.
--
Ashutosh