Commit 0d001f02 authored by Committed by Nobuhiro Iwamatsu
Revert "ravb: Fixed to be able to unload modules"
commit 77972b55fb9d35d4a6b0abca99abffaa4ec6a85b upstream. This reverts commit 1838d6c62f57836639bd3d83e7855e0ee4f6defc. This commit moved the ravb_mdio_init() call (and thus the of_mdiobus_register() call) from the ravb_probe() to the ravb_open() call. This causes a regression during system resume (s2idle/s2ram), as new PHY devices cannot be bound while suspended. During boot, the Micrel PHY is detected like this: Micrel KSZ9031 Gigabit PHY e6800000.ethernet-ffffffff:00: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=e6800000.ethernet-ffffffff:00, irq=228) ravb e6800000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off During system suspend, (A) defer_all_probes is set to true, and (B) usermodehelper_disabled is set to UMH_DISABLED, to avoid drivers being probed while suspended. A. If CONFIG_MODULES=n, phy_device_register() calling device_add() merely adds the device, but does not probe it yet, as really_probe() returns early due to defer_all_probes being set: dpm_resume+0x128/0x4f8 device_resume+0xcc/0x1b0 dpm_run_callback+0x74/0x340 ravb_resume+0x190/0x1b8 ravb_open+0x84/0x770 of_mdiobus_register+0x1e0/0x468 of_mdiobus_register_phy+0x1b8/0x250 of_mdiobus_phy_device_register+0x178/0x1e8 phy_device_register+0x114/0x1b8 device_add+0x3d4/0x798 bus_probe_device+0x98/0xa0 device_initial_probe+0x10/0x18 __device_attach+0xe4/0x140 bus_for_each_drv+0x64/0xc8 __device_attach_driver+0xb8/0xe0 driver_probe_device.part.11+0xc4/0xd8 really_probe+0x32c/0x3b8 Later, phy_attach_direct() notices no PHY driver has been bound, and falls back to the Generic PHY, leading to degraded operation: Generic PHY e6800000.ethernet-ffffffff:00: attached PHY driver [Generic PHY] (mii_bus:phy_addr=e6800000.ethernet-ffffffff:00, irq=POLL) ravb e6800000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off B. If CONFIG_MODULES=y, request_module() returns early with -EBUSY due to UMH_DISABLED, and MDIO initialization fails completely: mdio_bus e6800000.ethernet-ffffffff:00: error -16 loading PHY driver module for ID 0x00221622 ravb e6800000.ethernet eth0: failed to initialize MDIO PM: dpm_run_callback(): ravb_resume+0x0/0x1b8 returns -16 PM: Device e6800000.ethernet failed to resume: error -16 Ignoring -EBUSY in phy_request_driver_module(), like was done for -ENOENT in commit 21e194425abd65b5 ("net: phy: fix issue with loading PHY driver w/o initramfs"), would makes it fall back to the Generic PHY, like in the CONFIG_MODULES=n case. Signed-off-by: Geert Uytterhoeven <email@example.com> Cc: firstname.lastname@example.org Reviewed-by: Sergei Shtylyov <email@example.com> Signed-off-by: David S. Miller <firstname.lastname@example.org> Signed-off-by: Greg Kroah-Hartman <email@example.com> Signed-off-by: Nobuhiro Iwamatsu <firstname.lastname@example.org>
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