From 348ae2cb8b4b5f951959c0b055db7ca745806968 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Thu, 12 May 2022 10:42:02 +0200 Subject: [PATCH] usbnet: smsc95xx: Don't clear read-only PHY interrupt BugLink: https://bugs.launchpad.net/bugs/1990162 [ 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 # LAN9514/9512/9500 Tested-by: Ferry Toth # LAN9514 Signed-off-by: Lukas Wunner Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- drivers/net/usb/smsc95xx.c | 4 ---- 1 file changed, 4 deletions(-) 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_; -- 2.39.5