This is a note to let you know that I've just added the patch titled
usbnet: smsc95xx: Don't clear read-only PHY interrupt
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usbnet-smsc95xx-don-t-clear-read-only-phy-interrupt.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2c1c3a1806ffa081e67dd98bd100544ea82439ad
Author: Lukas Wunner <lukas@xxxxxxxxx>
Date: Thu May 12 10:42:02 2022 +0200
usbnet: smsc95xx: Don't clear read-only PHY interrupt
[ Upstream commit 3108871f19221372b251f7da1ac38736928b5b3a ]
Upon receiving data from the Interrupt Endpoint, the SMSC LAN95xx driver
attempts to clear the signaled interrupts by writing "all ones" to the
Interrupt Status Register.
However the driver only ever enables a single type of interrupt, namely
the PHY Interrupt. And according to page 119 of the LAN950x datasheet,
its bit in the Interrupt Status Register is read-only. There's no other
way to clear it than in a separate PHY register:
https://www.microchip.com/content/dam/mchp/documents/UNG/ProductDocuments/DataSheets/LAN950x-Data-Sheet-DS00001875D.pdf
Consequently, writing "all ones" to the Interrupt Status Register is
pointless and can be dropped.
Tested-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> # LAN9514/9512/9500
Tested-by: Ferry Toth <fntoth@xxxxxxxxx> # LAN9514
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 4e39e4345084..c33089168880 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -570,10 +570,6 @@ static int smsc95xx_link_reset(struct usbnet *dev)
unsigned long flags;
int ret;
- ret = smsc95xx_write_reg(dev, INT_STS, INT_STS_CLEAR_ALL_);
- if (ret < 0)
- return ret;
-
spin_lock_irqsave(&pdata->mac_cr_lock, flags);
if (pdata->phydev->duplex != DUPLEX_FULL) {
pdata->mac_cr &= ~MAC_CR_FDPX_;
