On 12/10/ , Quan, Evan wrote:
> [AMD Official Use Only]
>
>
>
> > -----Original Message-----
> > From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Lang
> > Yu
> > Sent: Thursday, December 9, 2021 4:49 PM
> > To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> > Cc: Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>; Lazar, Lijo
> > <Lijo.Lazar@xxxxxxx>; Huang, Ray <Ray.Huang@xxxxxxx>; Deucher,
> > Alexander <Alexander.Deucher@xxxxxxx>; Yu, Lang <Lang.Yu@xxxxxxx>;
> > Koenig, Christian <Christian.Koenig@xxxxxxx>
> > Subject: [PATCH 2/2] drm/amdgpu: add support for SMU debug option
> >
> > SMU firmware guys expect the driver maintains error context
> > and doesn't interact with SMU any more when SMU errors occurred.
> > That will aid in debugging SMU firmware issues.
> >
> > Add SMU debug option support for this request, it can be
> > enabled or disabled via amdgpu_smu_debug debugfs file.
> > When enabled, it brings hardware to a kind of halt state
> > so that no one can touch it any more in the envent of SMU
> > errors.
> >
> > Currently, dirver interacts with SMU via sending messages.
> > And threre are three ways to sending messages to SMU.
> > Handle them respectively as following:
> >
> > 1, smu_cmn_send_smc_msg_with_param() for normal timeout cases
> >
> > Halt on any error.
> >
> > 2, smu_cmn_send_msg_without_waiting()/smu_cmn_wait_for_response()
> > for longer timeout cases
> >
> > Halt on errors apart from ETIME. Otherwise this way won't work.
> >
> > 3, smu_cmn_send_msg_without_waiting() for no waiting cases
> >
> > Halt on errors apart from ETIME. Otherwise second way won't work.
> >
> > After halting, use BUG() to explicitly notify users.
> >
> > == Command Guide ==
> >
> > 1, enable SMU debug option
> >
> > # echo 1 > /sys/kernel/debug/dri/0/amdgpu_smu_debug
> >
> > 2, disable SMU debug option
> >
> > # echo 0 > /sys/kernel/debug/dri/0/amdgpu_smu_debug
> >
> > v4:
> > - Set to halt state instead of a simple hang.(Christian)
> >
> > v3:
> > - Use debugfs_create_bool().(Christian)
> > - Put variable into smu_context struct.
> > - Don't resend command when timeout.
> >
> > v2:
> > - Resend command when timeout.(Lijo)
> > - Use debugfs file instead of module parameter.
> >
> > Signed-off-by: Lang Yu <lang.yu@xxxxxxx>
> > ---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 3 +++
> > drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h | 5 +++++
> > drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c | 20
> > +++++++++++++++++++-
> > 3 files changed, 27 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > index 164d6a9e9fbb..86cd888c7822 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > @@ -1618,6 +1618,9 @@ int amdgpu_debugfs_init(struct amdgpu_device
> > *adev)
> > if (!debugfs_initialized())
> > return 0;
> >
> > + debugfs_create_bool("amdgpu_smu_debug", 0600, root,
> > + &adev->smu.smu_debug_mode);
> > +
> > ent = debugfs_create_file("amdgpu_preempt_ib", 0600, root, adev,
> > &fops_ib_preempt);
> > if (IS_ERR(ent)) {
> > diff --git a/drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h
> > b/drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h
> > index f738f7dc20c9..50dbf5594a9d 100644
> > --- a/drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h
> > +++ b/drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h
> > @@ -569,6 +569,11 @@ struct smu_context
> > struct smu_user_dpm_profile user_dpm_profile;
> >
> > struct stb_context stb_context;
> > + /*
> > + * When enabled, it makes SMU errors fatal.
> > + * (0 = disabled (default), 1 = enabled)
> > + */
> > + bool smu_debug_mode;
> [Quan, Evan] Can you expand this to bit mask(as ppfeaturemask)? So that in future we can add support for other debug features.
> > };
OK.
> >
> > struct i2c_adapter;
> > diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
> > b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
> > index 048ca1673863..84016d22c075 100644
> > --- a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
> > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
> > @@ -272,6 +272,11 @@ int smu_cmn_send_msg_without_waiting(struct
> > smu_context *smu,
> > __smu_cmn_send_msg(smu, msg_index, param);
> > res = 0;
> > Out:
> > + if (unlikely(smu->smu_debug_mode) && res && (res != -ETIME)) {
> > + amdgpu_device_halt(smu->adev);
> > + BUG();
> [Quan, Evan] I agree amdgpu_device_halt() is a good idea. Christian and Andrey can share you more insights about that.
> Do we still need the "BUG()" then?
The BUG() is used to explicitly notify users something went
wrong. Otherwise userspace may not know immediately.
FW guys request this in ticket.
Regards,
Lang
> BR
> Evan
> > + }
> > +
> > return res;
> > }
> >
> > @@ -288,9 +293,17 @@ int smu_cmn_send_msg_without_waiting(struct
> > smu_context *smu,
> > int smu_cmn_wait_for_response(struct smu_context *smu)
> > {
> > u32 reg;
> > + int res;
> >
> > reg = __smu_cmn_poll_stat(smu);
> > - return __smu_cmn_reg2errno(smu, reg);
> > + res = __smu_cmn_reg2errno(smu, reg);
> > +
> > + if (unlikely(smu->smu_debug_mode) && res && (res != -ETIME)) {
> > + amdgpu_device_halt(smu->adev);
> > + BUG();
> > + }
> > +
> > + return res;
> > }
> >
> > /**
> > @@ -357,6 +370,11 @@ int smu_cmn_send_smc_msg_with_param(struct
> > smu_context *smu,
> > if (read_arg)
> > smu_cmn_read_arg(smu, read_arg);
> > Out:
> > + if (unlikely(smu->smu_debug_mode) && res) {
> > + amdgpu_device_halt(smu->adev);
> > + BUG();
> > + }
> > +
> > mutex_unlock(&smu->message_lock);
> > return res;
> > }
> > --
> > 2.25.1
