On Thu, Mar 16, 2023 at 12:28:58PM +0530, Udipto Goswami wrote:
> When the dwc3 device is runtime suspended, various required clocks would
> get disabled and it is not guaranteed that access to any registers would
> work. Depending on the SoC glue, a register read could be as benign as
> returning 0 or be fatal enough to hang the system.
>
> In order to prevent such scenarios of fatal errors, bail out of debugfs
> function is dwc3 is suspended.
>
> Signed-off-by: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>
> ---
> v3: Replace pr_err to dev_err.
>
> drivers/usb/dwc3/debugfs.c | 60 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 60 insertions(+)
>
> diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
> index 850df0e6bcab..4a9d0994f3b4 100644
> --- a/drivers/usb/dwc3/debugfs.c
> +++ b/drivers/usb/dwc3/debugfs.c
> @@ -544,6 +544,12 @@ static int dwc3_link_state_show(struct seq_file *s, void *unused)
> u32 reg;
> u8 speed;
>
> + if (pm_runtime_suspended(dwc->dev)) {
> + dev_err(dwc->dev,
> + "Invalid operation, DWC3 suspended!");
> + return -EINVAL;
> + }
What prevents the device from being suspened right after you check this?
thanks,
greg k-h
