On Mon, 12 Oct 2015 09:00:21 +0200 Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > On Wed, Oct 07, 2015 at 07:52:21PM +0300, Peter Mamonov wrote: > > On Wed, 7 Oct 2015 17:40:24 +0200 > > > > Non-interruptible delays are needed here to prevent ehci_* > > > > functions re-entrance. The re-entrance occurs during a usb bus > > > > scan, after detection of a usb keyboard. As soon as a USB > > > > keyboard is detected, it's driver starts the poller, which > > > > interferes with the process of usb bus scan. However that last > > > > one delay may be interruptible. > > > > > > my problem is as soon as you start a usb control msg you block > > > everything > > > > > > nothing else can run in barebox > > > > > > can slow down barebox boot > > > > > > I do think we need a real mdelay_non_interruptible feature but > > > just forbidden to recall usb control msg. > > > But the rest of barebox can run durring those 5ms > > > > Well, I think it can be done by returning -EAGAIN on re-entrance > > detection in ehci_* functions [1], and skipping the poll in the > > keyboard driver. > > Could you tell us what you have done to get re-entrance problems? I > have just replaced the mdelay_non_interruptible with regular mdelay > in the ehci driver and didn't notice any problems. Could you verify > the _non_interruptible is still needed? If I revert the "usb: ehci-hcd: use mdelay_non_interruptible()" patch, while leaving the "usb: ehci-hcd: detect re-entrance" applied, I get the following messages after running the "usb" command: barebox:/ usb USB: scanning bus for devices... Bus 001 Device 001: ID 0000:0000 EHCI Host Controller Bus 001 Device 002: ID 0424:2514 Bus 001 Device 003: ID 413c:2112 Dell USB Wired Multimedia Keybo usb-keyboard usb1-0-0: USB keyboard found Bus 001 Device 004: ID 8564:1000 Mass Storage Device Using index 0 for the new disk usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-hub:usb1) usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-hub:usb1) usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-keyboard:usb1-0-0) usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-keyboard:usb1-0-0) usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-hub:usb1) usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-keyboard:usb1-0-0) usb-keyboard usb1-0-0: submit_int_msg: re-entrance 1 (usb-keyboard:usb1-0-0) Bus 001 Device 005: ID 0424:2514 5 USB Device(s) found According to the debug messages: submit_int_msg() is called by the usb-keyboard driver (from the poller function), while "usb-hub" driver is executing submit_control_msg() (which calls mdelay() and poller_call() subsequently). This occurs several times, until usb bus scan is completed. Probably the problem can be reproduced by adding more usb devices. > > Sascha > _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
