nit: The commit message title tag should be "r8152", instead of "r8151". On Mon, Feb 24, 2020 at 03:15:41PM +0800, You-Sheng Yang wrote: > Dell USB Type C docking WD19/WD19DC attaches additional peripherals as: > > /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M > |__ Port 1: Dev 11, If 0, Class=Hub, Driver=hub/4p, 5000M > |__ Port 3: Dev 12, If 0, Class=Hub, Driver=hub/4p, 5000M > |__ Port 4: Dev 13, If 0, Class=Vendor Specific Class, > Driver=r8152, 5000M > > where usb 2-1-3 is a hub connecting all USB Type-A/C ports on the dock. > > When hotplugging such dock with additional usb devices already attached on > it, the probing process may reset usb 2.1 port, therefore r8152 ethernet > device is also reset. However, during r8152 device init there are several > for-loops that, when it's unable to retrieve hardware registers due to > being discconected from USB, may take up to 14 seconds each in practice, > and that has to be completed before USB may re-enumerate devices on the > bus. As a result, devices attached to the dock will only be available > after nearly 1 minute after the dock was plugged in: > > [ 216.388290] [250] r8152 2-1.4:1.0: usb_probe_interface > [ 216.388292] [250] r8152 2-1.4:1.0: usb_probe_interface - got id > [ 258.830410] r8152 2-1.4:1.0 (unnamed net_device) (uninitialized): PHY not ready > [ 258.830460] r8152 2-1.4:1.0 (unnamed net_device) (uninitialized): Invalid header when reading pass-thru MAC addr > [ 258.830464] r8152 2-1.4:1.0 (unnamed net_device) (uninitialized): Get ether addr fail > > This can be reproduced on all kernel versions up to latest v5.6-rc2, but > after v5.5-rc7 the reproduce rate is dramatically lower to 1/30 or so > while it was around 1/2. > > The time consuming for-loops are at: > https://elixir.bootlin.com/linux/v5.5/source/drivers/net/usb/r8152.c#L3206 > https://elixir.bootlin.com/linux/v5.5/source/drivers/net/usb/r8152.c#L5400 > https://elixir.bootlin.com/linux/v5.5/source/drivers/net/usb/r8152.c#L5537 > > Signed-off-by: You-Sheng Yang <vicamo.yang@xxxxxxxxxxxxx> > --- > drivers/net/usb/r8152.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c > index 78ddbaf6401b..95b19ce96513 100644 > --- a/drivers/net/usb/r8152.c > +++ b/drivers/net/usb/r8152.c > @@ -3221,6 +3221,8 @@ static u16 r8153_phy_status(struct r8152 *tp, u16 desired) > } > > msleep(20); > + if (test_bit(RTL8152_UNPLUG, &tp->flags)) > + break; > } > > return data; > @@ -5402,7 +5404,10 @@ static void r8153_init(struct r8152 *tp) > if (ocp_read_word(tp, MCU_TYPE_PLA, PLA_BOOT_CTRL) & > AUTOLOAD_DONE) > break; > + > msleep(20); > + if (test_bit(RTL8152_UNPLUG, &tp->flags)) > + break; > } > > data = r8153_phy_status(tp, 0); > @@ -5539,7 +5544,10 @@ static void r8153b_init(struct r8152 *tp) > if (ocp_read_word(tp, MCU_TYPE_PLA, PLA_BOOT_CTRL) & > AUTOLOAD_DONE) > break; > + > msleep(20); > + if (test_bit(RTL8152_UNPLUG, &tp->flags)) > + break; > } > > data = r8153_phy_status(tp, 0); > -- > 2.25.0 >
