Re: [PATCH] drm/amd/pm: Fix a bug communicating with the SMU

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 2021-07-14 11:19 a.m., Alex Deucher wrote:
> On Mon, Jul 12, 2021 at 10:56 PM Lazar, Lijo <lijo.lazar@xxxxxxx> wrote:
>>
>>
>> On 7/12/2021 9:00 PM, Luben Tuikov wrote:
>>> This fixes a bug which if we probe a non-existing
>>> I2C device, and the SMU returns 0xFF, from then on
>>> we can never communicate with the SMU, because the
>>> code before this patch reads and interprets 0xFF
>>> as a terminal error, and thus we never write 0
>>> into register 90 to clear the status (and
>>> subsequently send a new command to the SMU.)
>>>
>>> It is not an error that the SMU returns status
>>> 0xFF. This means that the SMU executed the last
>>> command successfully (execution status), but the
>>> command result is an error of some sort (execution
>>> result), depending on what the command was.
>>>
>>> When doing a status check of the SMU, before we
>>> send a new command, the only status which
>>> precludes us from sending a new command is 0--the
>>> SMU hasn't finished executing a previous command,
>>> and 0xFC--the SMU is busy.
>>>
>>> This bug was seen as the following line in the
>>> kernel log,
>>>
>>> amdgpu: Msg issuing pre-check failed(0xff) and SMU may be not in the right state!
>>>
>>> when subsequent SMU commands, not necessarily
>>> related to I2C, were sent to the SMU.
>>>
>>> This patch fixes this bug.
>>>
>>> Cc: Alex Deucher <Alexander.Deucher@xxxxxxx>
>>> Cc: Evan Quan <evan.quan@xxxxxxx>
>>> Fixes: fcb1fe9c9e0031 ("drm/amd/powerplay: pre-check the SMU state before issuing message")
>>> Signed-off-by: Luben Tuikov <luben.tuikov@xxxxxxx>
>>> ---
>>>   drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c | 196 +++++++++++++++++++------
>>>   drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h |   3 +-
>>>   2 files changed, 152 insertions(+), 47 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
>>> index c902fdf322c1be..775eb50a2e49a6 100644
>>> --- a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
>>> +++ b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
>>> @@ -55,7 +55,7 @@
>>>
>>>   #undef __SMU_DUMMY_MAP
>>>   #define __SMU_DUMMY_MAP(type)       #type
>>> -static const char* __smu_message_names[] = {
>>> +static const char * const __smu_message_names[] = {
>>>       SMU_MESSAGE_TYPES
>>>   };
>>>
>>> @@ -76,46 +76,161 @@ static void smu_cmn_read_arg(struct smu_context *smu,
>>>       *arg = RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_82);
>>>   }
>>>
>>> -int smu_cmn_wait_for_response(struct smu_context *smu)
>>> +/**
>>> + * __smu_cmn_poll_stat -- poll for a status from the SMU
>>> + * smu: a pointer to SMU context
>>> + *
>>> + * Returns the status of the SMU, which could be,
>>> + * 0, the SMU is busy with your previous command;
>>> + * 1,    execution status: success, execution result: success;
>>> + * 0xFF, execution status: success, execution result: failure;
>>> + * 0xFE, unknown command;
>>> + * 0xFD, valid command, but bad (command) prerequisites;
>>> + * 0xFC, the command was rejected as the SMU is busy;
>>> + * 0xFB, "SMC_Result_DebugDataDumpEnd".
>>> + */
>> These are the response codes defined in header (0xFB is somehow missing)
>> // SMU Response Codes:
>> #define PPSMC_Result_OK                    0x1
>> #define PPSMC_Result_Failed                0xFF
>> #define PPSMC_Result_UnknownCmd            0xFE
>> #define PPSMC_Result_CmdRejectedPrereq     0xFD
>> #define PPSMC_Result_CmdRejectedBusy       0xFC
>>
>> It's better to use #defines for these, usually we follow a convention
>> like SMU_
> We could do a MAP_RESULT() macro like we do with the messages, etc. to
> make them per asic, but that may be overkill as I think these result
> codes have been the same across asics for a long time.

I think this would be best done in a subsequent/follow-up patch, since
it doesn't affect the behaviour of the system. I feel that such a change, while cosmetic,
would be somewhat involved and deserves its own patch and review, but for now,
we should get the system going.

I also think that ideally we'd want this to arrive from the SMU team perhaps,
so that we're impervious to such changes.

Regards,
Luben


>
> Alex
>
>> Ex:
>>         #define SMU_RESP_RESULT_OK 0x1
>>
>>
>>> +static u32 __smu_cmn_poll_stat(struct smu_context *smu)
>>>   {
>>>       struct amdgpu_device *adev = smu->adev;
>>> -     uint32_t cur_value, i, timeout = adev->usec_timeout * 20;
>>> +     int timeout = adev->usec_timeout * 20;
>>> +     u32 reg;
>>>
>>> -     for (i = 0; i < timeout; i++) {
>>> -             cur_value = RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90);
>>> -             if ((cur_value & MP1_C2PMSG_90__CONTENT_MASK) != 0)
>>> -                     return cur_value;
>>> +     for ( ; timeout > 0; timeout--) {
>>> +             reg = RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90);
>>> +             if ((reg & MP1_C2PMSG_90__CONTENT_MASK) != 0)
>>> +                     break;
>>>
>>>               udelay(1);
>>>       }
>>>
>>> -     /* timeout means wrong logic */
>>> -     if (i == timeout)
>>> -             return -ETIME;
>>> -
>>> -     return RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90);
>>> +     return reg;
>>>   }
>>>
>>> -int smu_cmn_send_msg_without_waiting(struct smu_context *smu,
>>> -                                  uint16_t msg, uint32_t param)
>>> +static void __smu_cmn_reg_print_error(struct smu_context *smu,
>>> +                                   u32 reg_c2pmsg_90,
>> Instead of using reg/regname in function, it would be better to name it
>> as smu_cmn_resp/smu_resp or similar to make it clear that we are
>> decoding smu response.
>>
>>> +                                   int msg_index,
>>> +                                   u32 param,
>>> +                                   enum smu_message_type msg)
>>>   {
>>>       struct amdgpu_device *adev = smu->adev;
>>> -     int ret;
>>> +     const char *message = smu_get_message_name(smu, msg);
>>>
>>> -     ret = smu_cmn_wait_for_response(smu);
>>> -     if (ret != 0x1) {
>>> -             dev_err(adev->dev, "Msg issuing pre-check failed(0x%x) and "
>>> -                    "SMU may be not in the right state!\n", ret);
>>> -             if (ret != -ETIME)
>>> -                     ret = -EIO;
>>> -             return ret;
>>> +     switch (reg_c2pmsg_90) {
>>> +     case 0:
>>> +             dev_err_ratelimited(adev->dev,
>>> +                                 "SMU: I'm not done with your previous command!");
>>> +             break;
>>> +     case 1:
>>> +             /* The SMU executed the command. It completed with a
>>> +              * successful result.
>>> +              */
>>> +             break;
>>> +     case 0xFF:
>>> +             /* The SMU executed the command. It completed with a
>>> +              * unsuccessful result.
>>> +              */
>>> +             break;
>>> +     case 0xFE:
>>> +             dev_err_ratelimited(adev->dev,
>>> +                                 "SMU: unknown command: index:%d param:0x%08X message:%s",
>>> +                                 msg_index, param, message);
>>> +             break;
>>> +     case 0xFD:
>>> +             dev_err_ratelimited(adev->dev,
>>> +                                 "SMU: valid command, bad prerequisites: index:%d param:0x%08X message:%s",
>>> +                                 msg_index, param, message);
>>> +             break;
>>> +     case 0xFC:
>>> +             dev_err_ratelimited(adev->dev,
>>> +                                 "SMU: I'm very busy for your command: index:%d param:0x%08X message:%s",
>>> +                                 msg_index, param, message);
>>> +             break;
>>> +     case 0xFB:
>>> +             dev_err_ratelimited(adev->dev,
>>> +                                 "SMU: I'm debugging!");
>>> +             break;
>>> +     default:
>>> +             dev_err_ratelimited(adev->dev,
>>> +                                 "SMU: response:0x%08X for index:%d param:0x%08X message:%s?",
>>> +                                 reg_c2pmsg_90, msg_index, param, message);
>>> +             break;
>>> +     }
>>> +}
>>> +
>>> +static int __smu_cmn_reg2errno(struct smu_context *smu, u32 reg_c2pmsg_90)
>> Same comment on naming - resp2errno?
>>> +{
>>> +     int res;
>>> +
>>> +     switch (reg_c2pmsg_90) {
>>> +     case 0:
>>> +             res = -ETIME;
>>> +             break;
>>> +     case 1:
>>> +             res = 0;
>>> +             break;
>>> +     case 0xFF:
>>> +             res = -EIO;
>>> +             break;
>>> +     case 0xFE:
>>> +             res = -EOPNOTSUPP;
>>> +             break;
>>> +     case 0xFD:
>>> +             res = -EIO;
>>> +             break;
>>> +     case 0xFC:
>>> +             res = -EBUSY;
>>> +             break;
>>> +     case 0xFB:
>>> +             res = -EIO;
>>> +             break;
>>> +     default:
>>> +             res = -EIO;
>>> +             break;
>>>       }
>>>
>>> +     return res;
>>> +}
>>> +
>>> +static void __smu_cmn_send_msg(struct smu_context *smu,
>>> +                            u16 msg,
>>> +                            u32 param)
>>> +{
>>> +     struct amdgpu_device *adev = smu->adev;
>>> +
>>>       WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90, 0);
>>>       WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_82, param);
>>>       WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_66, msg);
>>> +}
>>>
>>> -     return 0;
>>> +int smu_cmn_send_msg_without_waiting(struct smu_context *smu,
>>> +                                  uint16_t msg_index,
>>> +                                  uint32_t param)
>>> +{
>>> +     u32 reg;
>>> +     int res;
>>> +
>>> +     if (smu->adev->in_pci_err_recovery)
>>> +             return 0;
>>> +
>>> +     mutex_lock(&smu->message_lock);
>>> +     reg = __smu_cmn_poll_stat(smu);
>>> +     if (reg == 0 || reg == 0xFC) {
>> The problem with 0xFC check is it could be the response of a previous
>> message. It could mean that FW was busy when the prev message was sent,
>> not now.
>>
>> There is a default case (value not in any of the predefined error
>> codes), that should be considered here also. That happens sometimes and
>> usually that means FW is in undefined state.
>>
>>
>>> +             res = __smu_cmn_reg2errno(smu, reg);
>>> +             goto Out;
>> Label naming style, lower case?.
>>
>>> +     }
>>> +     __smu_cmn_send_msg(smu, msg_index, param);
>>> +     res = 0;
>>> +Out:
>>> +     mutex_unlock(&smu->message_lock);
>>> +     return res;
>>> +}
>>> +
>>> +int smu_cmn_wait_for_response(struct smu_context *smu)
>>> +{
>>> +     u32 reg;
>>> +
>>> +     reg = __smu_cmn_poll_stat(smu);
>>> +     return __smu_cmn_reg2errno(smu, reg);
>>>   }
>>>
>>>   int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
>>> @@ -123,8 +238,8 @@ int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
>>>                                   uint32_t param,
>>>                                   uint32_t *read_arg)
>>>   {
>>> -     struct amdgpu_device *adev = smu->adev;
>>> -     int ret = 0, index = 0;
>>> +     int res, index;
>>> +     u32 reg;
>>>
>>>       if (smu->adev->in_pci_err_recovery)
>>>               return 0;
>>> @@ -136,31 +251,20 @@ int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
>>>               return index == -EACCES ? 0 : index;
>>>
>>>       mutex_lock(&smu->message_lock);
>>> -     ret = smu_cmn_send_msg_without_waiting(smu, (uint16_t)index, param);
>>> -     if (ret)
>>> -             goto out;
>>> -
>>> -     ret = smu_cmn_wait_for_response(smu);
>>> -     if (ret != 0x1) {
>>> -             if (ret == -ETIME) {
>>> -                     dev_err(adev->dev, "message: %15s (%d) \tparam: 0x%08x is timeout (no response)\n",
>>> -                             smu_get_message_name(smu, msg), index, param);
>>> -             } else {
>>> -                     dev_err(adev->dev, "failed send message: %15s (%d) \tparam: 0x%08x response %#x\n",
>>> -                             smu_get_message_name(smu, msg), index, param,
>>> -                             ret);
>>> -                     ret = -EIO;
>>> -             }
>>> -             goto out;
>>> +     reg = __smu_cmn_poll_stat(smu);
>>> +     if (reg == 0 || reg == 0xFC) {
>> Same comments as for without_waiting case.
>>
>>> +             res = __smu_cmn_reg2errno(smu, reg);
>>> +             __smu_cmn_reg_print_error(smu, reg, index, param, msg);
>> This precheck fail print is missing in without_waiting message.
>>
>>> +             goto Out; >     }
>>> -
>>> +     __smu_cmn_send_msg(smu, (uint16_t) index, param);
>>> +     reg = __smu_cmn_poll_stat(smu);
>>> +     res = __smu_cmn_reg2errno(smu, reg);
>> Using smu_cmn_wait_for_response instead of these two makes the intent
>> clearer - that we are waiting for the response.
>>
>> We need a print here as well if the message has failed.
>>
>> Thanks,
>> Lijo
>>
>>>       if (read_arg)
>>>               smu_cmn_read_arg(smu, read_arg);
>>> -
>>> -     ret = 0; /* 0 as driver return value */
>>> -out:
>>> +Out:
>>>       mutex_unlock(&smu->message_lock);
>>> -     return ret;
>>> +     return res;
>>>   }
>>>
>>>   int smu_cmn_send_smc_msg(struct smu_context *smu,
>>> diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h
>>> index 9add5f16ff562a..16993daa2ae042 100644
>>> --- a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h
>>> +++ b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h
>>> @@ -27,7 +27,8 @@
>>>
>>>   #if defined(SWSMU_CODE_LAYER_L2) || defined(SWSMU_CODE_LAYER_L3) || defined(SWSMU_CODE_LAYER_L4)
>>>   int smu_cmn_send_msg_without_waiting(struct smu_context *smu,
>>> -                                  uint16_t msg, uint32_t param);
>>> +                                  uint16_t msg_index,
>>> +                                  uint32_t param);
>>>   int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
>>>                                   enum smu_message_type msg,
>>>                                   uint32_t param,
>>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&amp;data=04%7C01%7Cluben.tuikov%40amd.com%7C63c12227eaee4417d06c08d946dad4be%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637618727955855924%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=Au4k6zam4oVtRNl2JA%2BNEQTGjiOLxZULDKQnYDQg9ho%3D&amp;reserved=0

_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/amd-gfx



[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux