Messages in this thread | | | Date | Wed, 16 Jan 2013 10:00:47 -0500 (EST) | From | Alan Stern <> | Subject | Re: Linux 3.8-rc1 - another regression on USB :-( |
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On Tue, 15 Jan 2013, Woody Suwalski wrote:
> > 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,...
But apparently you don't insmod ehci-pci. That could cause problems, if your EHCI controller is PCI-based.
> If all USB is built as modules - I get read errors from USB drives when > accessing squash image, boot fails.
What read errors? What is the cause of these errors?
> 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.
Do have a dmesg log with timestamps so we can see where things go slow? I suggest enabling CONFIG_PRINTK_TIME and CONFIG_USB_DEBUG. You might even want CONFIG_USB_STORAGE_DEBUG, although that often logs too much information.
> If usb-common, usbcore and ehci-hcd are built-in, all works OK like > "before 3.8".
What about ehci-pci?
> 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.
Without knowing what these read errors are, it's hard to say anything about them.
Alan Stern
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