On 18/12/2020 03:16, Saravana Kannan wrote: > As discussed in LPC 2020, cyclic dependencies in firmware that couldn't > be broken using logic was one of the last remaining reasons > fw_devlink=on couldn't be set by default. > > This series changes fw_devlink so that when a cyclic dependency is found > in firmware, the links between those devices fallback to permissive mode > behavior. This way, the rest of the system still benefits from > fw_devlink, but the ambiguous cases fallback to permissive mode. > > Setting fw_devlink=on by default brings a bunch of benefits (currently, > only for systems with device tree firmware): > * Significantly cuts down deferred probes. > * Device probe is effectively attempted in graph order. > * Makes it much easier to load drivers as modules without having to > worry about functional dependencies between modules (depmod is still > needed for symbol dependencies). One issue we have come across with this is the of_mdio.c driver. On Tegra194 Jetson Xavier I am seeing the following ... boot: logs: [ 4.194791] WARNING KERN WARNING: CPU: 0 PID: 1 at /dvs/git/dirty/git-master_l4t-upstream/kernel/drivers/base/core.c:1189 device_links_driver_bound+0x240/0x260 boot: logs: [ 4.207683] WARNING KERN Modules linked in: boot: logs: [ 4.210691] WARNING KERN CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.11.0-rc3-next-20210112-gdf869cab4b35 #1 boot: logs: [ 4.219221] WARNING KERN Hardware name: NVIDIA Jetson AGX Xavier Developer Kit (DT) boot: logs: [ 4.225628] WARNING KERN pstate: 80400009 (Nzcv daif +PAN -UAO -TCO BTYPE=--) boot: logs: [ 4.231542] WARNING KERN pc : device_links_driver_bound+0x240/0x260 boot: logs: [ 4.236587] WARNING KERN lr : device_links_driver_bound+0xf8/0x260 boot: logs: [ 4.241560] WARNING KERN sp : ffff800011f4b980 boot: logs: [ 4.244819] WARNING KERN x29: ffff800011f4b980 x28: ffff00008208a0a0 boot: logs: [ 4.250051] WARNING KERN x27: ffff00008208a080 x26: 00000000ffffffff boot: logs: [ 4.255271] WARNING KERN x25: 0000000000000003 x24: ffff800011b99000 boot: logs: [ 4.260489] WARNING KERN x23: 0000000000000001 x22: ffff800011df14f0 boot: logs: [ 4.265706] WARNING KERN x21: ffff800011f4b9f8 x20: ffff800011df1000 boot: logs: [ 4.270934] WARNING KERN x19: ffff00008208a000 x18: 0000000000000005 boot: logs: [ 4.276166] WARNING KERN x17: 0000000000000007 x16: 0000000000000001 boot: logs: [ 4.281382] WARNING KERN x15: ffff000080030c90 x14: ffff0000805c9df8 boot: logs: [ 4.286618] WARNING KERN x13: 0000000000000000 x12: ffff000080030c90 boot: logs: [ 4.291847] WARNING KERN x11: ffff0000805c9da8 x10: 0000000000000040 boot: logs: [ 4.297061] WARNING KERN x9 : ffff000080030c98 x8 : 0000000000000000 boot: logs: [ 4.302291] WARNING KERN x7 : 0000000000000009 x6 : 0000000000000000 boot: logs: [ 4.307509] WARNING KERN x5 : ffff000080100000 x4 : 0000000000000000 boot: logs: [ 4.312739] WARNING KERN x3 : ffff800011df1e38 x2 : ffff000080908c10 boot: logs: [ 4.317956] WARNING KERN x1 : 0000000000000001 x0 : ffff0000809ca400 boot: logs: [ 4.323183] WARNING KERN Call trace: boot: logs: [ 4.325593] WARNING KERN device_links_driver_bound+0x240/0x260 boot: logs: [ 4.330301] WARNING KERN driver_bound+0x70/0xd0 boot: logs: [ 4.333740] WARNING KERN device_bind_driver+0x50/0x60 boot: logs: [ 4.337671] WARNING KERN phy_attach_direct+0x258/0x2e0 boot: logs: [ 4.341718] WARNING KERN phylink_of_phy_connect+0x7c/0x140 boot: logs: [ 4.346081] WARNING KERN stmmac_open+0xb04/0xc70 boot: logs: [ 4.349612] WARNING KERN __dev_open+0xe0/0x190 boot: logs: [ 4.352972] WARNING KERN __dev_change_flags+0x16c/0x1b8 boot: logs: [ 4.357081] WARNING KERN dev_change_flags+0x20/0x60 boot: logs: [ 4.360856] WARNING KERN ip_auto_config+0x2a0/0xfe8 boot: logs: [ 4.364633] WARNING KERN do_one_initcall+0x58/0x1b8 boot: logs: [ 4.368405] WARNING KERN kernel_init_freeable+0x1ec/0x240 boot: logs: [ 4.372698] WARNING KERN kernel_init+0x10/0x110 boot: logs: [ 4.376130] WARNING KERN ret_from_fork+0x10/0x18 So looking at this change does this mean that the of_mdio needs to be converted to a proper driver? I would have thought that this will be seen on several platforms. Cheers Jon -- nvpublic
