From: Woody Suwalski <terraluna977@gmail.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Andreas Mohr <andi@lisas.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
USB list <linux-usb@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 3.8-rc1 - another regression on USB :-(
Date: Tue, 15 Jan 2013 23:26:20 -0500 [thread overview]
Message-ID: <50F62BEC.4060602@gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1301121237570.32458-100000@netrider.rowland.org>
Alan Stern wrote:
> On Sat, 12 Jan 2013, Andreas Mohr wrote:
>
>> There's of course the EHCI vs. UHCI(/OHCI) duality
>> (EHCI host controller responsible for high speed transfers,
>> the other for 1.1 full speed, both serving the same port connectors).
>> So if the coordination between the two is a problem,
>> you might end up with merely full speed on a 2.0 port.
>>
>> And with drivers builtin vs. module, the init sequence/timing
>> might possibly be affected - right?
>> Perhaps this got worsened by semi-recent driver init kernel changes?
>> (AFAIR the kernel was changed to init more things in parallel,
>> for faster bootup). So maybe that affected EHCI vs. UHCI coordination timing.
> Another important change is that the EHCI driver is now split into two
> modules. That can slow down loading and affect the timing.
>
> Alan Stern
>
My testcase is a live initramfs + squash root.
The boot logic is as stable as can be - unchanged since 2.6.2x kernels.
And it was working fine till 3.8-rc1.
The modules are insmoded in a fixed order:
usb-common, usbcore, xhci-hcd, ehci-hcd, uhci-hcd, ohci-hcd, usbhid,
usb_storage,...
If all USB is built as modules - I get read errors from USB drives when
accessing squash image, boot fails.
If usb-common and usbcore are built in, system seems to crawl with a
very slow USB, but boots. That could be caused by timing between hcd
modules.
If usb-common, usbcore and ehci-hcd are built-in, all works OK like
"before 3.8".
I was testing on machines without xhci or ohci hardware, so these
drivers probably are not playing any role.
I have retried initramfs with a 1s sleep between insmods to verify if it
is timing - still the same read errors - so the main issue is _not_ timing.
The read errors problem is 100% reproducible for me, the blocks where
read fails are not fixed - every (failed) boot errors start appearing in
a bit different location.
Just selecting a differently - configured kernel image makes the boot
work, so it is not a problem of squash image, USB drive, squashfs driver.
Scratching my head loudly,
Woody
next prev parent reply other threads:[~2013-01-16 4:26 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-22 2:00 Linux 3.8-rc1 Linus Torvalds
2012-12-22 2:57 ` Steven Rostedt
2013-01-16 9:25 ` David Nyström
2012-12-23 13:39 ` [Regression w/ patch] Media commit causes user space to misbahave (was: Re: Linux 3.8-rc1) Rafael J. Wysocki
2012-12-23 14:08 ` Mauro Carvalho Chehab
2012-12-23 17:36 ` Linus Torvalds
2012-12-23 20:21 ` Mauro Carvalho Chehab
2012-12-23 22:29 ` Linus Torvalds
2012-12-24 19:28 ` Mauro Carvalho Chehab
2012-12-23 20:39 ` Laurent Pinchart
2012-12-23 22:04 ` linux-next stats (Was: " Stephen Rothwell
[not found] ` <50D764BA.1030501@gmail.com>
2012-12-23 22:35 ` Linux 3.8-rc1 - another regression on USB :-( Linus Torvalds
2012-12-23 23:27 ` Greg Kroah-Hartman
2012-12-24 3:46 ` Woody Suwalski
2012-12-28 23:12 ` Woody Suwalski
2013-01-01 15:17 ` INVALID " Woody Suwalski
2013-01-02 13:41 ` Woody Suwalski
2013-01-12 13:16 ` Andreas Mohr
2013-01-12 16:54 ` Oliver Neukum
2013-01-12 17:38 ` Alan Stern
2013-01-16 4:26 ` Woody Suwalski [this message]
2013-01-16 8:25 ` Oliver Neukum
2013-01-16 15:00 ` Alan Stern
2013-01-17 2:25 ` Woody Suwalski
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