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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?6IjzxOYrjOceEZLNht6ehzFD2SFyJfjvOQHk4Aul+DwfuYqsf1aGuKuCmg+l?= =?us-ascii?Q?J8mRjuLU9GjvKoQnf0UL8AebBPHu+Hn/lI4sTBKdG44KfrCAW8UEU3b19wgF?= =?us-ascii?Q?ZmFXHSeepxddHAVt/eBllU7uSmn9pjPT6hItLnpjMbQ5ZbjHhVJpfsIGo5dh?= =?us-ascii?Q?vZJhnrPx8oE3WYZN4G0NF8lb7HOb2YoJDYiypdmtukzJd7y03hVzZn9Cwnz4?= =?us-ascii?Q?FCySmuWvgQR0J5UdaH7JxokUD6z/zZ0QNeDQd5Bbw3FMKz/VJDMz+fWIuj0C?= =?us-ascii?Q?Z1/pLhaX3PeiGji44oFA6tK8SBAtlTUIWDMxGtFKeAyJESOypnK9O3cVqrgw?= =?us-ascii?Q?JzN/Lgu4cQlk/jTmD4bSmv6X4/hJdkSMKZXoHXXD1nhvmA/isQYvYZDMFbIc?= =?us-ascii?Q?z6+UH9Fje0XE+WpKB11xP0hlkLxgzCtC6Swlz7EP4wwROey4f8+nUc5eYcmi?= =?us-ascii?Q?KaxnK47KmwOrmbyOzHpb+pj7VQelEou/X4clp4v5G+GUF2mFqzvAbY5a0FIx?= =?us-ascii?Q?ZewIfQHAfge2vD6r/k9m9SdiJT54ScLya2M0Tx1Dv4MyabKlHuc06bRtM1t2?= =?us-ascii?Q?UMIF0VZBw8tOA+PK1IJDIqcYsiNOx/562j15KNwUc4Oh/OOx4b938aoot6hG?= =?us-ascii?Q?rrERh2jaxQ4kL4RExjiCJBbjMbhmWYVLZ/R0MKop2FkKQCa4v0j2kXefwXam?= =?us-ascii?Q?AnpLENjA57tKZvE2a0ZToj5bFaSC8u2yq372Fjre0IEm9Wrt8DLwOGztwFVA?= =?us-ascii?Q?J3zcNokO5pydErPOXucYYWS8iLNcqjbSOAQf5hOv+fg94uaoxo/wd/ZOOQqn?= =?us-ascii?Q?4d5qyx8/IMCP6XgCxsUFPKSUOdv/TW/blTz6KmUmgUAINTXwbRUpfBMfSAiP?= =?us-ascii?Q?3KmoFfVVdQTJ6ZH/iGYOnu2Vv83soJrQ6J20nOGY1uvvrD5yEWGgs3Equrxz?= =?us-ascii?Q?IrNfqIjPacqvNnBXD6SMouZNx8DWfEbdRrwM0Cy7S8s+1+Bg7MtRjGK2yO7J?= =?us-ascii?Q?+nBxBKhLMesb0YHwA9Y3xuZriug53N8b8dHcUN0Gq/MVCO0s3pYL4AxecV9i?= =?us-ascii?Q?E4j7pQ7Swr4JEZoWyHlnElH3SEbv9ho3gMKOty1MEF5KUtEofzQ80vzCDwJe?= =?us-ascii?Q?y2VbK6EVwDDfoHZvpFhPOoR3EC8v1G1+Z83dlBBhqHYQEdz7RaVhpCw/IEUr?= =?us-ascii?Q?zmVIQ8JaAu4/EGt9TdAB8f0Y62U1b622LVjXiFXSxZv8UwaPu2I+p8V3NZKS?= =?us-ascii?Q?NsJUnArj4+D1+ABhrVrNjKBhNUEDwi5/YHCGuVA1P5ZHry820UydqC+B7ul2?= =?us-ascii?Q?JPOPu3Gly3ucHJsv21QOg0KMO/XLInj4pLZnoizsYFyFFwOgSrjsZS7vDQOE?= =?us-ascii?Q?+WFfg2faRJTrMWXs8Jv4ViMR4iD2gnaxVsH4Kd9sq+svmCT5ZqESTB8LGsFe?= =?us-ascii?Q?Hi31hOU9gkaUT+hB7ALJvsbGuaSPzcr9Ya/lpe6jvDpyfAmJpnVC01lsGL3u?= =?us-ascii?Q?bxrq1e9qKu1cU+84eg7ZK7FudV/oUaOAmJd5stKYne5dHT9PnGmf4fFREVSX?= =?us-ascii?Q?JHM2WOKQl0yXcDXjBXlWXTl+k+n0jRAATVZT4wkdSiYgNppKN224HQbyZB6n?= =?us-ascii?Q?xw=3D=3D?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 4b3df196-bc75-4a6d-0711-08dc1b45283e X-MS-Exchange-CrossTenant-AuthSource: VE1PR04MB7374.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Jan 2024 12:25:02.4274 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: eDN6sbyTbW6kyMieKDWOfqIrf/TtP3mJdU/En8kJfNFhCqlrxBSbhRYnSHoE1Iqdlg4+FeXsLZ7BuSaRFWRU5Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU2PR04MB8902 Hi Andrew, On Sat, Jan 20, 2024 at 08:21:25PM +0100, Andrew Lunn wrote: > When there is no device on the bus for a given address, the pull up > resistor on the data line results in the read returning 0xffff. The > phylib core code understands this when scanning for devices on the > bus, and a number of MDIO bus masters make use of this as a way to > indicate they cannot perform the read. > > Make us of this as a minimal fix for stable where the mv88e6xxx s/us/use/ Also, what is the "proper" fix if this is the minimal one for stable? > returns EOPNOTSUPP when the hardware does not support C45, but phylib > interprets this as a fatal error, which it should not be. I think the commit message is a bit backwards, it starts with an explanation of the solution without ever clarifying exactly what is the problem. At least it could have referenced the old thread which explains that: https://lore.kernel.org/netdev/CAO-L_44YVi0HDk4gC9QijMZrYNGoKtfH7qsXOwtDwM4VrFRDHw@mail.gmail.com/ > > Cc: stable@vger.kernel.org > Reported-by: Tim Menninger > Fixes: 1a136ca2e089 ("net: mdio: scan bus based on bus capabilities for C22 and C45") > Fixes: da099a7fb13d ("net: phy: Remove probe_capabilities") > Signed-off-by: Andrew Lunn > --- > drivers/net/dsa/mv88e6xxx/chip.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c > index 383b3c4d6f59..614cabb5c1b0 100644 > --- a/drivers/net/dsa/mv88e6xxx/chip.c > +++ b/drivers/net/dsa/mv88e6xxx/chip.c > @@ -3659,7 +3659,7 @@ static int mv88e6xxx_mdio_read_c45(struct mii_bus *bus, int phy, int devad, > int err; > > if (!chip->info->ops->phy_read_c45) > - return -EOPNOTSUPP; > + return 0xffff; > > mv88e6xxx_reg_lock(chip); > err = chip->info->ops->phy_read_c45(chip, bus, phy, devad, reg, &val); > -- > 2.43.0 > Is this an RFC pending testing from Tim? Or have you reproduced the problem and confirmed that this fixes it? It's not clear how the old thread ended.