Hi all,
On Tue, 19 Nov 2019, Andy Shevchenko wrote:
On Mon, Nov 18, 2019 at 07:15:05PM +0100, Marek Behún wrote:
When CONFIG_RESET_CONTROLLER is disabled, the
devm_reset_control_get_exclusive function returns -ENOTSUPP. This is not
handled in subsequent check and then the mdio device fails to probe.
When CONFIG_RESET_CONTROLLER is enabled, its code checks in OF for reset
device, and since it is not present, returns -ENOENT. -ENOENT is handled.
Add -ENOTSUPP also.
This happened to me when upgrading kernel on Turris Omnia. You either
have to enable CONFIG_RESET_CONTROLLER or use this patch.
In the long term prospective shouldn't it use
reset_control_get_optional_exclusive() instead?
I was thinking the same, hence I tried.
Without a reset (i.e. the returned reset is now NULL instead of
-ENOENT):
WARNING: CPU: 1 PID: 120 at drivers/base/dd.c:519 really_probe+0xb0/0x314
Modules linked in:
CPU: 1 PID: 120 Comm: kworker/1:2 Not tainted 5.4.0-rc8-koelsch-08348-gbc6931ed2139022b-dirty #615
Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
Workqueue: events deferred_probe_work_func
[<c020e268>] (unwind_backtrace) from [<c020a428>] (show_stack+0x10/0x14)
[<c020a428>] (show_stack) from [<c07a075c>] (dump_stack+0x88/0xa8)
[<c07a075c>] (dump_stack) from [<c0220980>] (__warn+0xb8/0xd0)
[<c0220980>] (__warn) from [<c0220a08>] (warn_slowpath_fmt+0x70/0x9c)
[<c0220a08>] (warn_slowpath_fmt) from [<c05150b0>] (really_probe+0xb0/0x314)
[<c05150b0>] (really_probe) from [<c0515598>] (driver_probe_device+0x13c/0x154)
[<c0515598>] (driver_probe_device) from [<c0513784>] (bus_for_each_drv+0xa0/0xb4)
[<c0513784>] (bus_for_each_drv) from [<c05153c0>] (__device_attach+0xac/0x124)
[<c05153c0>] (__device_attach) from [<c05143f0>] (bus_probe_device+0x28/0x80)
[<c05143f0>] (bus_probe_device) from [<c051227c>] (device_add+0x4d8/0x698)
[<c051227c>] (device_add) from [<c0581110>] (phy_device_register+0x3c/0x74)
[<c0581110>] (phy_device_register) from [<c0675efc>] (of_mdiobus_register_phy+0x144/0x17c)
[<c0675efc>] (of_mdiobus_register_phy) from [<c06760f8>] (of_mdiobus_register+0x1c4/0x2d0)
[<c06760f8>] (of_mdiobus_register) from [<c0589f18>] (sh_eth_drv_probe+0x778/0x8ac)
[<c0589f18>] (sh_eth_drv_probe) from [<c0516ce8>] (platform_drv_probe+0x48/0x94)
[<c0516ce8>] (platform_drv_probe) from [<c05151f8>] (really_probe+0x1f8/0x314)
[<c05151f8>] (really_probe) from [<c0515598>] (driver_probe_device+0x13c/0x154)
The difference with the non-optional case is that
__devm_reset_control_get() registers a cleanup function if there's
no error condition, even for NULL (which is futile, will send a patch).
However, more importantly, mdiobus_register_reset() calls a devm_*()
function on "&mdiodev->dev" ("mdio_bus ee700000.ethernet-ffffffff:01"),
which is a different device than the one being probed
(("ee700000.ethernet"), see also the callstack below).
In fact "&mdiodev->dev" hasn't been probed yet, leading to the WARNING
when it is probed later.
[<c0582de8>] (mdiobus_register_device) from [<c05810e0>] (phy_device_register+0xc/0x74)
[<c05810e0>] (phy_device_register) from [<c0675ef4>] (of_mdiobus_register_phy+0x144/0x17c)
[<c0675ef4>] (of_mdiobus_register_phy) from [<c06760f0>] (of_mdiobus_register+0x1c4/0x2d0)
[<c06760f0>] (of_mdiobus_register) from [<c0589f0c>] (sh_eth_drv_probe+0x778/0x8ac)
[<c0589f0c>] (sh_eth_drv_probe) from [<c0516ce8>] (platform_drv_probe+0x48/0x94)
Has commit 71dd6c0dff51b5f1 ("net: phy: add support for
reset-controller") been tested with an actual reset present?
Are Ethernet drivers not (no longer) allowed to register MDIO busses?
Thanks!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
