[Intel-gfx] [PATCH 3/3] drm/i915/guc: sleep on enable

[Chris Wilson]

Quoting Daniele Ceraolo Spurio (2018-10-15 19:33:26)
> 
> 
> On 14/10/18 10:02, Chris Wilson wrote:
> > Seems like there's a missing ack before the guc is ready for commands.
> > 
> 
> I'm assuming you're running without HuC since the HuC auth H2G comes 
> before this one.

https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_4981/fi-apl-guc/boot0.log
i915.enable_guc=3 
<7>[    6.877175] [drm:intel_uc_fw_fetch [i915]] GuC fw fetch i915/bxt_guc_ver9_29.bin
<7>[    6.877268] [drm:intel_uc_fw_fetch [i915]] GuC fw fetch PENDING
<7>[    6.879780] [drm:intel_uc_fw_fetch [i915]] GuC fw size 146432 ptr 000000003fdb20d0
<7>[    6.879869] [drm:intel_uc_fw_fetch [i915]] GuC fw version 9.29 (wanted 9.29)
<7>[    6.880425] [drm:intel_uc_fw_fetch [i915]] GuC fw fetch SUCCESS
<7>[    6.880723] [drm:intel_uc_fw_fetch [i915]] HuC fw fetch i915/bxt_huc_ver01_07_1398.bin
<7>[    6.880807] [drm:intel_uc_fw_fetch [i915]] HuC fw fetch PENDING
<7>[    6.882529] [drm:intel_uc_fw_fetch [i915]] HuC fw size 154432 ptr 000000000aad61c4
<7>[    6.882621] [drm:intel_uc_fw_fetch [i915]] HuC fw version 1.7 (wanted 1.7)
<7>[    6.883098] [drm:intel_uc_fw_fetch [i915]] HuC fw fetch SUCCESS

> What we're polling to indicate load completion (GS_UKERNEL_READY) is 
> definitely what the firmware uses to signal readiness. The other check 
> we do (GS_MIA_CORE_STATE) should only apply for rc6 scenarios. From what 
> I can see from the firmware code, all the initialization steps are done 
> before GS_UKERNEL_READY is written to the status register so there 
> shouldn't be any missing acks in principle.

> Is the GuC returning anything in the scratch 0 register? It should be 
> printed out by the H2G error message. The value of the status register 
> (0xc000) could also provide interesting debug info.

When do you want to know? As you are probably aware, our first
indication of failure is from wait_for_guc_preempt_report() and
the wait there on report->report_return_status timing out.

Michel asked what was the value when it timed out, but alas apl-guc was
not available for comment.
-Chris