Re: [PATCH v3 04/12] bus: mhi: core: Move to SYS_ERROR regardless of RDDM capability

From: Manivannan Sadhasivam
Date: Fri Oct 30 2020 - 09:53:00 EST


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@xxxxxxxxxxxxxx>
> ---
> 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;
> }
> --
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