Re: [PATCH v1] smsc911x: add second read of EEPROM mac when possible corruption seen
From: Jakub Kicinski <kuba@kernel.org>
Date: 2025-09-01 20:57:13
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On Thu, 28 Aug 2025 16:44:52 -0500 Colin Foster wrote:
When the EEPROM MAC is read by way of ADDRH, it can return all 0s the first time. Subsequent reads succeed. Re-read the ADDRH when this behaviour is observed, in an attempt to correctly apply the EEPROM MAC address.
Please name the device, and FW version if applicable, on which you observe the issue.
quoted hunk ↗ jump to hunk
Signed-off-by: Colin Foster <colin.foster@in-advantage.com> --- drivers/net/ethernet/smsc/smsc911x.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c index a2e511912e6a9..63ed221edc00a 100644 --- a/drivers/net/ethernet/smsc/smsc911x.c +++ b/drivers/net/ethernet/smsc/smsc911x.c@@ -2162,8 +2162,20 @@ static const struct net_device_ops smsc911x_netdev_ops = { static void smsc911x_read_mac_address(struct net_device *dev) { struct smsc911x_data *pdata = netdev_priv(dev); - u32 mac_high16 = smsc911x_mac_read(pdata, ADDRH); - u32 mac_low32 = smsc911x_mac_read(pdata, ADDRL); + u32 mac_high16, mac_low32; + + mac_high16 = smsc911x_mac_read(pdata, ADDRH); + mac_low32 = smsc911x_mac_read(pdata, ADDRL); + + /*
nit: netdev multi-line comment style doesn't place /* on a separate line:
+ * The first mac_read always returns 0. Re-read it to get the + * full MAC
Always? Strange, why did nobody notice until now?
+ */
+ if (mac_high16 == 0) {
+ SMSC_TRACE(pdata, probe, "Re-read MAC ADDRH\n");
+ mac_high16 = smsc911x_mac_read(pdata, ADDRH);
+ }u8 addr[ETH_ALEN];
Please don't add code in the middle of variable declarations -- pw-bot: cr