bugGNU GRUB - Bugs: bug #47406, GRUB2 detects constant addition of...

 
 

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bug #47406: GRUB2 detects constant addition of nonexistent USB devices

Submitted by:  Timothy Pearson <tpearson>
Submitted on:  Mon 14 Mar 2016 05:51:05 AM UTC  
 
Category: BootingSeverity: Major
Priority: 6Item Group: None
Status: NonePrivacy: Public
Assigned to: NoneOriginator Name: 
Open/Closed: OpenRelease: 
Release: Git masterReproducibility: None
Planned Release: 2.02

Mon 28 Mar 2016 10:12:50 PM UTC, comment #5:

It turns out that the observed symptoms were related to enabling USB debug support in coreboot on the AMD platforms. Disabling USB debug support resolved the GRUB issues.

I am not sure if this is something that GRUB should detect / handle. If not please feel free to mark this request invalid.

Thanks!

Timothy Pearson <tpearson>
Wed 16 Mar 2016 03:12:02 AM UTC, comment #4:

Thank you for the clarification.

Interestingly I am unable to replicate the aforementioned USB problems with a stock coreboot build. This appears to be specific to Libreboot (a coreboot downstream distribution). I will update as I have more information.

Timothy Pearson <tpearson>
Tue 15 Mar 2016 05:48:40 PM UTC, comment #3:

detect_dev is called for every port constantly and its purpose is to detect if new devices are connected and it's lightweight if none is. "Oscilating" is because it actually shows status for different ports. It's piossible that ohci.mod is culprit as it's less tested that ehci for coreboot, hence I ask to remove it from mkrescue command line. Make sure that all connected devices are either USB 2.0 or later or connect through a hub

Vladimir Serbinenko <phcoder>
Project Administrator
Mon 14 Mar 2016 08:41:30 PM UTC, comment #2:

I am not familiar with GRUB's code, however those messages should only be printed if the grub_ohci_detect_dev function is being called repeatedly. Am I misunderstanding the purpose of that function?

Decoding the flags reveals the status register is changing between:

OHCI_CTRL_IR

and

OHCI_CTRL_CBSR
OHCI_CTRL_IR
OHCI_CTRL_RWC

I am not familiar with the details of OHCI operation. Is this normal / expected behavior when no USB devices are attached?

If there is anything I should provide to debug the user-visible problem (namely severe USB keyboard input lag and extremely slow USB boot) please let me know.

Thanks!

Timothy Pearson <tpearson>
Mon 14 Mar 2016 08:27:27 PM UTC, comment #1:

What makes you think that there is a detected constant addition of USB devices? CHANGED bit is not set. Can you try removing OHCI module altogether and see if the problem disappears?

Vladimir Serbinenko <phcoder>
Project Administrator
Mon 14 Mar 2016 05:51:05 AM UTC, original submission:

When booted from coreboot on the KFSN4-DRE, KGPE-D16, or KCMA-D8 systems, GRUB2 operates extremely slowly, constantly detecting new USB devices even when no USB devices are actually present. Verbose logging shows a continuous stream of the following messages:

bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x303
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x100
bus/usb/ohci.c:1308: detect_dev status=0x303
bus/usb/ohci.c:1308: detect_dev status=0x100

This constant activity makes GRUB2 effectively unusable; USB keystrokes take seconds to process per keystroke and booting from USB is all but impossible.

The affected chipsets thus far are:
nVidia CK804
AMD SB700

Timothy Pearson <tpearson>

 

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Depends on the following items: None found

Items that depend on this one: None found

 

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  • -unavailable- added by phcoder (Posted a comment)
  • -unavailable- added by tpearson (Submitted the item)
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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Tue 11 Oct 2016 12:36:02 PM UTCphcoderPriority5 - Normal=>6
    Tue 15 Mar 2016 05:48:49 PM UTCphcoderPlanned ReleaseNone=>2.02

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