Re: [PATCH] drm/amdgpu: add mb for si

[Lazar, Lijo]

On 11/25/2022 7:43 AM, Quan, Evan wrote:
> [AMD Official Use Only - General]
>
>
>
> > -----Original Message-----
> > From: Lazar, Lijo <Lijo.Lazar@xxxxxxx>
> > Sent: Thursday, November 24, 2022 6:49 PM
> > To: Quan, Evan <Evan.Quan@xxxxxxx>; 李真能 <lizhenneng@xxxxxxxxxx>;
> > Michel Dänzer <michel.daenzer@xxxxxxxxxxx>; Koenig, Christian
> > <Christian.Koenig@xxxxxxx>; Deucher, Alexander
> > <Alexander.Deucher@xxxxxxx>
> > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Pan, Xinhui <Xinhui.Pan@xxxxxxx>;
> > linux-kernel@xxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > Subject: Re: [PATCH] drm/amdgpu: add mb for si
> >
> >
> >
> > On 11/24/2022 4:11 PM, Lazar, Lijo wrote:
> > > On 11/24/2022 3:34 PM, Quan, Evan wrote:
> > > > [AMD Official Use Only - General]
> > > >
> > > > Could the attached patch help?
> > > >
> > > > Evan
> > > > > -----Original Message-----
> > > > > From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf
> > Of ???
> > > > > Sent: Friday, November 18, 2022 5:25 PM
> > > > > To: Michel Dänzer <michel.daenzer@xxxxxxxxxxx>; Koenig, Christian
> > > > > <Christian.Koenig@xxxxxxx>; Deucher, Alexander
> > > > > <Alexander.Deucher@xxxxxxx>
> > > > > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Pan, Xinhui <Xinhui.Pan@xxxxxxx>;
> > > > > linux-kernel@xxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > > > > Subject: Re: [PATCH] drm/amdgpu: add mb for si
> > > > >
> > > > >
> > > > > 在 2022/11/18 17:18, Michel Dänzer 写道:
> > > > > > On 11/18/22 09:01, Christian König wrote:
> > > > > > > Am 18.11.22 um 08:48 schrieb Zhenneng Li:
> > > > > > > > During reboot test on arm64 platform, it may failure on boot, so
> > > > > > > > add this mb in smc.
> > > > > > > >
> > > > > > > > The error message are as follows:
> > > > > > > > [    6.996395][ 7] [  T295] [drm:amdgpu_device_ip_late_init
> > > > > > > > [amdgpu]] *ERROR*
> > > > > > > >                    late_init of IP block <si_dpm> failed -22 [
> > > > > > > > 7.006919][ 7] [  T295] amdgpu 0000:04:00.0:
> > > The issue is happening in late_init() which eventually does
> > >
> > >       ret = si_thermal_enable_alert(adev, false);
> > >
> > > Just before this, si_thermal_start_thermal_controller is called in
> > > hw_init and that enables thermal alert.
> > >
> > > Maybe the issue is with enable/disable of thermal alerts in quick
> > > succession. Adding a delay inside si_thermal_start_thermal_controller
> > > might help.
> > On a second look, temperature range is already set as part of
> > si_thermal_start_thermal_controller in hw_init
> > https://elixir.bootlin.com/linux/v6.1-
> > rc6/source/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c#L6780
> >
> > There is no need to set it again here -
> >
> > https://elixir.bootlin.com/linux/v6.1-
> > rc6/source/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c#L7635
> >
> > I think it is safe to remove the call from late_init altogether. Alex/Evan?
> [Quan, Evan] Yes, it makes sense to me. But I'm not sure whether that’s related with the issue here.
> Since per my understandings, if the issue is caused by double calling of thermal_alert enablement, it will fail every time.
> That cannot explain why adding some delays or a mb() calling can help.

The side effect of the patch is just some random delay introduced for 
every SMC message

The issue happens in late_init(). Between late_init() and dpm 
enablement, there are many smc messages sent which don't have this 
issue. So I think the issue is not with FW not running.

Thus the only case I see is enable/disable of thermal alert in random 
succession.

Thanks,

Lijo

> BR
> Evan
> > Thanks,
> > Lijo
> >
> > > Thanks,
> > > Lijo
> > >
> > > > > > > > amdgpu_device_ip_late_init failed [    7.014224][ 7] [  T295] amdgpu
> > > > > > > > 0000:04:00.0: Fatal error during GPU init
> > > > > > > Memory barries are not supposed to be sprinkled around like this,
> > you
> > > > > need to give a detailed explanation why this is necessary.
> > > > > > > Regards,
> > > > > > > Christian.
> > > > > > >
> > > > > > > > Signed-off-by: Zhenneng Li <lizhenneng@xxxxxxxxxx>
> > > > > > > > ---
> > > > > > > >      drivers/gpu/drm/amd/pm/legacy-dpm/si_smc.c | 2 ++
> > > > > > > >      1 file changed, 2 insertions(+)
> > > > > > > >
> > > > > > > > diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/si_smc.c
> > > > > > > > b/drivers/gpu/drm/amd/pm/legacy-dpm/si_smc.c
> > > > > > > > index 8f994ffa9cd1..c7656f22278d 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/pm/legacy-dpm/si_smc.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/si_smc.c
> > > > > > > > @@ -155,6 +155,8 @@ bool amdgpu_si_is_smc_running(struct
> > > > > > > > amdgpu_device *adev)
> > > > > > > >          u32 rst = RREG32_SMC(SMC_SYSCON_RESET_CNTL);
> > > > > > > >          u32 clk = RREG32_SMC(SMC_SYSCON_CLOCK_CNTL_0);
> > > > > > > >      +    mb();
> > > > > > > > +
> > > > > > > >          if (!(rst & RST_REG) && !(clk & CK_DISABLE))
> > > > > > > >              return true;
> > > > > > In particular, it makes no sense in this specific place, since it
> > > > > > cannot directly
> > > > > affect the values of rst & clk.
> > > > >
> > > > > I thinks so too.
> > > > >
> > > > > But when I do reboot test using nine desktop machines,  there maybe
> > > > > report
> > > > > this error on one or two machines after Hundreds of times or
> > > > > Thousands of
> > > > > times reboot test, at the beginning, I use msleep() instead of mb(),
> > > > > these
> > > > > two methods are all works, but I don't know what is the root case.
> > > > >
> > > > > I use this method on other verdor's oland card, this error message are
> > > > > reported again.
> > > > >
> > > > > What could be the root reason?
> > > > >
> > > > > test environmen:
> > > > >
> > > > > graphics card: OLAND 0x1002:0x6611 0x1642:0x1869 0x87
> > > > >
> > > > > driver: amdgpu
> > > > >
> > > > > os: ubuntu 2004
> > > > >
> > > > > platform: arm64
> > > > >
> > > > > kernel: 5.4.18