linux-kernel - Re: [PATCH v3 04/12] bus: mhi: core: Move to SYS

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Message-ID: <20201030135218.GG3818@Mani-XPS-13-9360>
Date:   Fri, 30 Oct 2020 19:22:18 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Bhaumik Bhatt <bbhatt@...eaurora.org>
Cc:     linux-arm-msm@...r.kernel.org, hemantk@...eaurora.org,
        jhugo@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 04/12] bus: mhi: core: Move to SYS_ERROR regardless of
 RDDM capability

On Thu, Oct 29, 2020 at 09:10:49PM -0700, Bhaumik Bhatt wrote:
> In some cases, the entry of device to RDDM execution environment
> can occur after a significant amount of time has elapsed and a
> SYS_ERROR state change event has already arrived.

I don't quite understand this statement. Can you elaborate? This doesn't
relate to what the patch is doing.

> This can result
> in scenarios where MHI controller and client drivers are unaware
> of the error state of the device. Remove the check for rddm_image
> when processing the SYS_ERROR state change as it is present in
> mhi_pm_sys_err_handler() already and prevent further activity
> until the expected RDDM execution environment change occurs or
> the controller driver decides further action.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>
> ---
>  drivers/bus/mhi/core/main.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index 2cff5dd..1f32d67 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -733,19 +733,15 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
>  				break;
>  			case MHI_STATE_SYS_ERR:
>  			{
> -				enum mhi_pm_state new_state;
> -
> -				/* skip SYS_ERROR handling if RDDM supported */
> -				if (mhi_cntrl->ee == MHI_EE_RDDM ||
> -				    mhi_cntrl->rddm_image)
> -					break;
> +				enum mhi_pm_state state = MHI_PM_STATE_MAX;
>  
>  				dev_dbg(dev, "System error detected\n");
>  				write_lock_irq(&mhi_cntrl->pm_lock);
> -				new_state = mhi_tryset_pm_state(mhi_cntrl,
> +				if (mhi_cntrl->ee != MHI_EE_RDDM)

But you are still checking for RDDM EE?

Please explain why you want to skip RDDM check.

Thanks,
Mani

> +					state = mhi_tryset_pm_state(mhi_cntrl,
>  							MHI_PM_SYS_ERR_DETECT);
>  				write_unlock_irq(&mhi_cntrl->pm_lock);
> -				if (new_state == MHI_PM_SYS_ERR_DETECT)
> +				if (state == MHI_PM_SYS_ERR_DETECT)
>  					mhi_pm_sys_err_handler(mhi_cntrl);
>  				break;
>  			}
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>