zd1211rw: handle lost read-reg interrupts

Device losses read-reg interrupts. By looking at usbmon it appears that
USB_INT_ID_RETRY_FAILED can override USB_INT_ID_REGS. This causes read
command to timeout, usually under heavy TX.

Fix by retrying read registers again if USB_INT_ID_RETRY_FAILED is received
while waiting for USB_INT_ID_REGS.

However USB_INT_ID_REGS is not always lost but is received after
USB_INT_ID_RETRY_FAILED and is usually received by the retried read
command. USB_INT_ID_REGS of the retry is then left unhandled and might
be received by next read command. Handle this by ignoring previous
USB_INT_ID_REGS that doesn't match current read command request.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/net/wireless/zd1211rw/zd_usb.h b/drivers/net/wireless/zd1211rw/zd_usb.h
index bf94284..99193b4 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.h
+++ b/drivers/net/wireless/zd1211rw/zd_usb.h
@@ -144,6 +144,8 @@ struct usb_int_retry_fail {
 
 struct read_regs_int {
 	struct completion completion;
+	struct usb_req_read_regs *req;
+	unsigned int req_count;
 	/* Stores the USB int structure and contains the USB address of the
 	 * first requested register before request.
 	 */
@@ -169,7 +171,8 @@ struct zd_usb_interrupt {
 	void *buffer;
 	dma_addr_t buffer_dma;
 	int interval;
-	u8 read_regs_enabled:1;
+	atomic_t read_regs_enabled;
+	u8 read_regs_int_overridden:1;
 };
 
 static inline struct usb_int_regs *get_read_regs(struct zd_usb_interrupt *intr)