On Mon, Feb 10, 2025 at 07:57:20AM -0600, Matt Lee wrote:
> This reverts a previously submitted patch where the slow retransmit was removed.
What is that git commit id you are reverting? Please list it and mark
the Fixes: and cc: stable tag as needed.
>
> Previously, the max3421 driver would immediately retry transmissions
> indefinitely
> upon receiving a NAK response, leading to potential stalls.
Odd line-wrapping :(
>
> This patch re-introduces a limit (`NAK_MAX_FAST_RETRANSMITS`) on how
> many times a
> request is retransmitted immediately. After reaching this limit, the driver
> falls back to a slower retransmit strategy using `max3421_slow_retransmit()`.
>
> This improves robustness when dealing with unresponsive USB devices.
>
> Signed-off-by: Matt Lee <matt@xxxxxxxxxx>
> ---
> drivers/usb/host/max3421-hcd.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/usb/host/max3421-hcd.c b/drivers/usb/host/max3421-hcd.c
> index 1234567..abcdef0 100644
> --- a/drivers/usb/host/max3421-hcd.c
> +++ b/drivers/usb/host/max3421-hcd.c
> @@ -72,6 +72,12 @@
> #define USB_MAX_FRAME_NUMBER 0x7ff
> #define USB_MAX_RETRIES 3 /* # of retries before error is reported */
>
> +/*
> + * Max. # of times we're willing to retransmit a request immediately in
> + * response to a NAK. Afterwards, we fall back on trying once a frame.
> + */
> +#define NAK_MAX_FAST_RETRANSMITS 2
> +
> #define POWER_BUDGET 500 /* in mA; use 8 for low-power port testing */
>
> /* Port-change mask: */
> @@ -924,8 +930,11 @@ max3421_handle_error(struct usb_hcd *hcd
> * Device wasn't ready for data or has no data
> * available: retry the packet again.
> */
> + if (max3421_ep->naks++ < NAK_MAX_FAST_RETRANSMITS) {
> max3421_next_transfer(hcd, 1);
> switch_sndfifo = 0;
> + } else
> + max3421_slow_retransmit(hcd);
Did you run scripts/checkpatch.pl on this change?
And why is 2 ok? How did that number get picked?
thanks,
greg k-h
