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USB: MAX3421: Handle USB NAK correctly

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A USB peripheral can respond with a NAK if it is not yet ready to
send/receive data. In this case, the transaction should be retried. The
MAX3421 driver did do this, and switched to a different type of retry
after a number of 'fast' retries. On at least some USB flash devices,
this second type of retry never succeeds. This patch changes the
behaviour so that 'fast' retries continue.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20230127024734.8777-1-mark.tomlinson@alliedtelesis.co.nz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mark Tomlinson 2023-01-27 15:47:34 +13:00 committed by Greg Kroah-Hartman
parent 7194e5e090
commit ff826648e1
1 changed files with 2 additions and 11 deletions
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13
drivers/usb/host/max3421-hcd.c
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@ -72,12 +72,6 @@
#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
* resposne 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: */
@ -924,11 +918,8 @@ max3421_handle_error(struct usb_hcd *hcd, u8 hrsl)
* 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);
max3421_next_transfer(hcd, 1);
switch_sndfifo = 0;
break;
}
if (switch_sndfifo)