Re: [PATCH] drm/amdgpu: show gfx clock gating status to user

[Alex Deucher <alexdeucher-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Wed, Jan 4, 2017 at 1:52 AM, Huang Rui <ray.huang@amd.com> wrote:
> On Wed, Jan 04, 2017 at 10:21:44AM +0800, Huang Rui wrote:
>> On Tue, Jan 03, 2017 at 11:02:09PM +0800, Deucher, Alexander wrote:
>> > > -----Original Message-----
>> > > From: Huang Rui [mailto:ray.huang@amd.com]
>> > > Sent: Tuesday, January 03, 2017 5:47 AM
>> > > To: Deucher, Alexander; amd-gfx@lists.freedesktop.org
>> > > Cc: Zhu, Rex; Mao, David; Fu, Ping; Huang, Ray
>> > > Subject: [PATCH] drm/amdgpu: show gfx clock gating status to user
>> > >
>> > > Signed-off-by: Huang Rui <ray.huang@amd.com>
>> > > ---
>> > >  drivers/gpu/drm/amd/amdgpu/amdgpu.h    | 1 +
>> > >  drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 5 +++++
>> > >  drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c  | 2 ++
>> > >  drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c  | 2 ++
>> > >  drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c  | 3 +++
>> > >  5 files changed, 13 insertions(+)
>> > >
>> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> > > index 96eeea7..989d311 100644
>> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> > > @@ -1033,6 +1033,7 @@ struct amdgpu_gfx {
>> > >   struct amdgpu_irq_src           priv_inst_irq;
>> > >   /* gfx status */
>> > >   uint32_t                        gfx_current_status;
>> > > + bool                            cg_enabled;
>> > >   /* ce ram size*/
>> > >   unsigned                        ce_ram_size;
>> > >   struct amdgpu_cu_info           cu_info;
>> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> > > index a7c7657..10f2eab 100644
>> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> > > @@ -1543,6 +1543,11 @@ static int amdgpu_debugfs_pm_info(struct
>> > > seq_file *m, void *data)
>> > >   struct amdgpu_device *adev = dev->dev_private;
>> > >   struct drm_device *ddev = adev->ddev;
>> > >
>> > > + if (adev->gfx.cg_enabled)
>> > > +         seq_printf(m, "GFX Clock Gating: Enabled\n");
>> > > + else
>> > > +         seq_printf(m, "GFX Clock Gating: Disabled\n");
>> > > +
>> >
>> >
>> > I think it would be better to print the cg_flags and pg_flags (both as a mask and in human readable form) so we know exactly cg and pg features are enabled.
>> >
>>
>> It's probable better. Let me revise this patch and send it later.
>>
>
> Hi Alex,
>
> There is one issue on tonga, polaris10, and polaris11, they use smu to
> control clock gating. And flags are below, not use adev->cg_flags. It
> cannot indicate clock gating status from adev->cg_flags and the
> cg_flags/pg_flags is marked supported state by HW, not runtime enablement state:
>
> #define PP_STATE_CG             0x01
> #define PP_STATE_LS             0x02
> #define PP_STATE_DS             0x04
> #define PP_STATE_SD             0x08
> #define PP_STATE_SUPPORT_CG     0x10
> #define PP_STATE_SUPPORT_LS     0x20
> #define PP_STATE_SUPPORT_DS     0x40
> #define PP_STATE_SUPPORT_SD     0x80
>
> I think shall we combine them with AMD_CG_SUPPORT_GFX_MGCG and etc.?
> Try to find unified flags to control clock gating and power gating...

I think we can still stick to the cg_flags.  The smu cg control
messages are derived from the cg_flags, they are just more coarse
grained.  cg_flags indicated the supported state, but unless there is
a problem, the driver will attempt to enable all of the features set
in cg_flags so we can use cg_flags for enablement as well.  For
tracking purposes, just add adev->cg_enabled and pg_enabled and set
the bits in the clockgating and powergating IP functions based on the
current state.  While some blocks are static, GFX supports automatic
clockgating so it's unless you've specifically disabled it, it's
enabled dynamically.  If you really want the current status, you'll
need to read the gfx cg status registers to check the current clock
state.

Alex
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