diff mbox series

[v2,1/2] Revert "drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh"

Message ID 1598354482-15491-2-git-send-email-mkshah@codeaurora.org
State Superseded
Headers show
Series [v2,1/2] Revert "drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh" | expand

Commit Message

Maulik Shah Aug. 25, 2020, 11:21 a.m. UTC 
Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
for rpmh") was written to fix a bug seen in an unmerged series that
implemented a struct generic_pm_domain::power_off() callback calling
rpmh_flush(). See stack trace below.

     Call trace:
      dump_backtrace+0x0/0x174
      show_stack+0x20/0x2c
      dump_stack+0xc8/0x124
      lockdep_rcu_suspicious+0xe4/0x104
      __tcs_buffer_write+0x230/0x2d0
      rpmh_rsc_write_ctrl_data+0x210/0x270
      rpmh_flush+0x84/0x24c
      rpmh_domain_power_off+0x78/0x98
      _genpd_power_off+0x40/0xc0
      genpd_power_off+0x168/0x208

Later the final merged solution is to use CPU PM notification to invoke
rpmh_flush() and power_off() callback of genpd is not implemented in the
driver.

CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify()
and how it calls rcu_irq_enter_irqson() before calling the notifiers).

Remove this change since RCU will not be idle during CPU PM notifications
hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint
prevented rpmh driver to be loadable module as these are not exported
symbols.

This reverts commit efde2659b0fe835732047357b2902cca14f054d9.

Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bjorn Andersson Aug. 27, 2020, 1:53 a.m. UTC | #1 
On Tue 25 Aug 06:21 CDT 2020, Maulik Shah wrote:

> Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
> for rpmh") was written to fix a bug seen in an unmerged series that
> implemented a struct generic_pm_domain::power_off() callback calling
> rpmh_flush(). See stack trace below.
> 
>      Call trace:
>       dump_backtrace+0x0/0x174
>       show_stack+0x20/0x2c
>       dump_stack+0xc8/0x124
>       lockdep_rcu_suspicious+0xe4/0x104
>       __tcs_buffer_write+0x230/0x2d0
>       rpmh_rsc_write_ctrl_data+0x210/0x270
>       rpmh_flush+0x84/0x24c
>       rpmh_domain_power_off+0x78/0x98
>       _genpd_power_off+0x40/0xc0
>       genpd_power_off+0x168/0x208
> 
> Later the final merged solution is to use CPU PM notification to invoke
> rpmh_flush() and power_off() callback of genpd is not implemented in the
> driver.
> 
> CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify()
> and how it calls rcu_irq_enter_irqson() before calling the notifiers).
> 
> Remove this change since RCU will not be idle during CPU PM notifications
> hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint
> prevented rpmh driver to be loadable module as these are not exported
> symbols.
> 
> This reverts commit efde2659b0fe835732047357b2902cca14f054d9.
> 
> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> ---
>  drivers/soc/qcom/rpmh-rsc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index ae66757..fabe390d 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
> @@ -495,7 +495,7 @@ static void __tcs_buffer_write(struct rsc_drv *drv, int tcs_id, int cmd_id,
>  		write_tcs_cmd(drv, RSC_DRV_CMD_MSGID, tcs_id, j, msgid);
>  		write_tcs_cmd(drv, RSC_DRV_CMD_ADDR, tcs_id, j, cmd->addr);
>  		write_tcs_cmd(drv, RSC_DRV_CMD_DATA, tcs_id, j, cmd->data);
> -		trace_rpmh_send_msg_rcuidle(drv, tcs_id, j, msgid, cmd);
> +		trace_rpmh_send_msg(drv, tcs_id, j, msgid, cmd);
>  	}
>  
>  	write_tcs_reg(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, tcs_id, cmd_complete);
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
John Stultz Sept. 28, 2020, 8:47 p.m. UTC | #2 
On Tue, Aug 25, 2020 at 4:22 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
> for rpmh") was written to fix a bug seen in an unmerged series that
> implemented a struct generic_pm_domain::power_off() callback calling
> rpmh_flush(). See stack trace below.
>
>      Call trace:
>       dump_backtrace+0x0/0x174
>       show_stack+0x20/0x2c
>       dump_stack+0xc8/0x124
>       lockdep_rcu_suspicious+0xe4/0x104
>       __tcs_buffer_write+0x230/0x2d0
>       rpmh_rsc_write_ctrl_data+0x210/0x270
>       rpmh_flush+0x84/0x24c
>       rpmh_domain_power_off+0x78/0x98
>       _genpd_power_off+0x40/0xc0
>       genpd_power_off+0x168/0x208
>
> Later the final merged solution is to use CPU PM notification to invoke
> rpmh_flush() and power_off() callback of genpd is not implemented in the
> driver.
>
> CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify()
> and how it calls rcu_irq_enter_irqson() before calling the notifiers).
>
> Remove this change since RCU will not be idle during CPU PM notifications
> hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint
> prevented rpmh driver to be loadable module as these are not exported
> symbols.
>
> This reverts commit efde2659b0fe835732047357b2902cca14f054d9.
>
> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>

Hey Maulik!
  Thanks so much for sending out this series!  I noticed this hasn't
made it to -next yet, so would it be good to resubmit it?

thanks
-john
Maulik Shah Sept. 29, 2020, 8:53 a.m. UTC | #3 
Hi,

On 9/29/2020 2:17 AM, John Stultz wrote:
> On Tue, Aug 25, 2020 at 4:22 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>> Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
>> for rpmh") was written to fix a bug seen in an unmerged series that
>> implemented a struct generic_pm_domain::power_off() callback calling
>> rpmh_flush(). See stack trace below.
>>
>>       Call trace:
>>        dump_backtrace+0x0/0x174
>>        show_stack+0x20/0x2c
>>        dump_stack+0xc8/0x124
>>        lockdep_rcu_suspicious+0xe4/0x104
>>        __tcs_buffer_write+0x230/0x2d0
>>        rpmh_rsc_write_ctrl_data+0x210/0x270
>>        rpmh_flush+0x84/0x24c
>>        rpmh_domain_power_off+0x78/0x98
>>        _genpd_power_off+0x40/0xc0
>>        genpd_power_off+0x168/0x208
>>
>> Later the final merged solution is to use CPU PM notification to invoke
>> rpmh_flush() and power_off() callback of genpd is not implemented in the
>> driver.
>>
>> CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify()
>> and how it calls rcu_irq_enter_irqson() before calling the notifiers).
>>
>> Remove this change since RCU will not be idle during CPU PM notifications
>> hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint
>> prevented rpmh driver to be loadable module as these are not exported
>> symbols.
>>
>> This reverts commit efde2659b0fe835732047357b2902cca14f054d9.
>>
>> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> Cc: John Stultz <john.stultz@linaro.org>
>> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
>> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
>> Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
>> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> Hey Maulik!
>    Thanks so much for sending out this series!  I noticed this hasn't
> made it to -next yet, so would it be good to resubmit it?
>
> thanks
> -john

Sure i will resend the series.

Thanks,
Maulik
diff mbox series

Patch

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index ae66757..fabe390d 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -495,7 +495,7 @@  static void __tcs_buffer_write(struct rsc_drv *drv, int tcs_id, int cmd_id,
 		write_tcs_cmd(drv, RSC_DRV_CMD_MSGID, tcs_id, j, msgid);
 		write_tcs_cmd(drv, RSC_DRV_CMD_ADDR, tcs_id, j, cmd->addr);
 		write_tcs_cmd(drv, RSC_DRV_CMD_DATA, tcs_id, j, cmd->data);
-		trace_rpmh_send_msg_rcuidle(drv, tcs_id, j, msgid, cmd);
+		trace_rpmh_send_msg(drv, tcs_id, j, msgid, cmd);
 	}
 
 	write_tcs_reg(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, tcs_id, cmd_complete);