Bug 158781 - ppc64: Kernel Panic on I2C Bus in New Apple G5 Logic Board < 2.6.12
ppc64: Kernel Panic on I2C Bus in New Apple G5 Logic Board < 2.6.12
Status: CLOSED RAWHIDE
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
4
powerpc Linux
medium Severity medium
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Assigned To: David Woodhouse
Brian Brock
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2005-05-25 13:42 EDT by Daniel Shay
Modified: 2007-11-30 17:11 EST (History)
2 users (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2005-06-04 01:37:23 EDT
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Description Daniel Shay 2005-05-25 13:42:39 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4

Description of problem:
Kernel problems related to the newest revision of the Apple G5 Dual Processor Systems.

Reference:

http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.12-rc5

Benjamin Herrenschmidt <benh@kernel.crashing.org>:
    [PATCH] ppc64: Fix booting on latest G5 models

    The latest speedbumped Apple G5 models have a "bug" in the Open Firmware
    device tree that lacks the proper interrupt routing information for the
    northbridge i2c controller.  Apple's driver silently falls back into a
    sub-optimal "polled" mode (heh, maybe they didn't even notice the bug
    because of that :), our driver didn't properly check and crashes :(

    This patch fixes our driver to not crash, and adds code to the
    prom_init() OF trampoline code that detects the "bug" and adds the
    missing information back for this chipset revision.  This fixes booting
    and thermal control on these models.

    Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Benjamin Herrenschmidt <benh@kernel.crashing.org>:
    [PATCH] ppc64: Fix g5 hw timebase sync

    The hardware sync of the timebase on SMP G5s uses a black magic
    incantation to the i2c clock chip that was inspired from what Darwin
    does.

    However, this was an earlier version of Darwin that was ...  buggy !
    heh.  This causes the latest models to break though when starting SMP,
    so it's worth fixing.

    Here's a new version of the incantation based on careful transcription
    of the said incantations as found in the latest version of apple's
    temple.

    Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>



Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1.Boot any Linux PPC64 Kernel < 2.6.12
2.Kernel Panic After I2C Probe
 

Additional info:
Comment 1 Dave Jones 2005-05-26 20:34:25 EDT
The kernel in rawhide today should have this fixed, as it includes -rc5
Comment 2 Daniel Shay 2005-06-02 17:16:10 EDT
Installed and running 2.6.11-1.1366_FC4-ppc from the rawhide yesterday 06/01/2005.

Thanks

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