On Wed, 11 Jan 2023, Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx> wrote: > On Wed, Jan 11, 2023 at 03:18:38PM +0200, Jani Nikula wrote: >> On Wed, 11 Jan 2023, Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx> wrote: >> > From: Aravind Iddamsetty <aravind.iddamsetty@xxxxxxxxx> >> > >> > During module load not all the punit transaction have completed >> > and we might end up timing out, as shown by the following >> > warning: >> >> Root cause? >> >> > >> > i915 0000:4d:00.0: drm_WARN_ON_ONCE(timeout_base_ms > 3) >> > >> > Wait 10 seconds for the punit to settle and complete any >> > outstanding transactions upon module load. >> > >> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7814 >> > >> >> No blank lines between the tag lines please. > > I don't consider "Closes:" to be a tag even if someone is using > it as such. AFAIK is not mentioned it in any of the kernel docs > (e.g. Documentation/process/maintainer-tip.rst). Basically all of the Something: lines should be bundled together. BR, Jani. > > Not to confuse it with a normal tag, I wanted to put it in > parenthesis or rephrase it. > >> > Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@xxxxxxxxx> >> > Co-developed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> >> > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> >> > Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/intel_pcode.c | 35 ++++++++++++++++++++++++++---- >> > 1 file changed, 31 insertions(+), 4 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/i915/intel_pcode.c b/drivers/gpu/drm/i915/intel_pcode.c >> > index a234d9b4ed14..3db2ba439bb5 100644 >> > --- a/drivers/gpu/drm/i915/intel_pcode.c >> > +++ b/drivers/gpu/drm/i915/intel_pcode.c >> > @@ -204,15 +204,42 @@ int skl_pcode_request(struct intel_uncore *uncore, u32 mbox, u32 request, >> > #undef COND >> > } >> > >> > +static int pcode_init_wait(struct intel_uncore *uncore, int timeout_ms) >> > +{ >> > + if (__intel_wait_for_register_fw(uncore, >> > + GEN6_PCODE_MAILBOX, >> > + GEN6_PCODE_READY, 0, >> > + 500, timeout_ms, >> > + NULL)) >> > + return -EPROBE_DEFER; >> >> This is already done within skl_pcode_request -> skl_pcode_try_request >> -> __snb_pcode_rw path, with waits in skl_pcode_request. > > the idea is to check for PCODE_READY even before checking if > data are sent/received by pcode. And this is only during boot > time. While skl_pcode_request is called in other contexts as > well. > > In other words here I want to start the communication when I > already know that the punit is ready. Otherwise I would hit an > -EAGAIN and fail. > >> Is there anyone who still understands what's being waited for, where, >> for how long, and why in the different code paths? I know I don't, and >> this isn't helping. > > I think it depends on hardware. There are some documents roaming > around with some boot time and reset time calculation. > >> There's also no explanation on the -EPROBE_DEFER return in the commit >> message or comments or anywhere. > > we haven't really failed, right? We just need some time for the > punit to be ready and try to probe again (remember we are here in > module probe). > > Thanks for the review, > Andi > >> Again, root cause? >> >> BR, >> Jani. >> >> >> > + >> > + return skl_pcode_request(uncore, >> > + DG1_PCODE_STATUS, >> > + DG1_UNCORE_GET_INIT_STATUS, >> > + DG1_UNCORE_INIT_STATUS_COMPLETE, >> > + DG1_UNCORE_INIT_STATUS_COMPLETE, timeout_ms); >> > +} >> > + >> > int intel_pcode_init(struct intel_uncore *uncore) >> > { >> > + int err; >> > + >> > if (!IS_DGFX(uncore->i915)) >> > return 0; >> > >> > - return skl_pcode_request(uncore, DG1_PCODE_STATUS, >> > - DG1_UNCORE_GET_INIT_STATUS, >> > - DG1_UNCORE_INIT_STATUS_COMPLETE, >> > - DG1_UNCORE_INIT_STATUS_COMPLETE, 180000); >> > + /* >> > + * Wait 10 seconds so that the punit to settle and complete >> > + * any outstanding transactions upon module load >> > + */ >> > + err = pcode_init_wait(uncore, 10000); >> > + >> > + if (err) { >> > + drm_notice(&uncore->i915->drm, >> > + "Waiting for HW initialisation...\n"); >> > + err = pcode_init_wait(uncore, 180000); >> > + } >> > + >> > + return err; >> > } >> > >> > int snb_pcode_read_p(struct intel_uncore *uncore, u32 mbcmd, u32 p1, u32 p2, u32 *val) >> >> -- >> Jani Nikula, Intel Open Source Graphics Center -- Jani Nikula, Intel Open Source Graphics Center
