Ubuntu
u-boot-linaro package

OMAP 4460 based pandas run too hot at current operating point

Bug #867670 reported by John Rigby on 2011-10-04

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	u-boot-linaro (Ubuntu)	Fix Released	High	John Rigby
Nominated for Oneiric by Ricardo Salveti

Bug Description

With both A9 cores loaded 4460 reaches max temperature in about 30s at the current operating point of 930MHz. The operating point should be lowered to 700MHz.

SRU Info:

This bug affects all 4460 based panda and blaze platforms.

Test case is to boot a 4460 based panda and run a something that pegs both cpus.

The fix is in upstream git.linaro.org (comment #2). This fix has been tested and shown to fix the problem with no regression (comment #4 and #5).

See original description

Related branches

lp:u-boot-linaro

lp:~linaro-foundations/u-boot-linaro/stable

lp:ubuntu/precise/u-boot-linaro

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-04:

From Sebastien Jan:

It appears the panda heats more than I thought (and much more that the blaze), and by loading the 2 cores I can quite easily reach max temperature at 920MHz (it takes around 30s on my board!).
At 700MHz, the temperature still increases but much slower. So if the A9 cores do not run at 100% all the time we shall be ok.
So for now, we definitely need this change if we don't want to run with a heatsink...

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-04:

A patch to lower the operating point to 700MHz has been applied to upstream u-boot-linaro on git.linaro.org:

http://git.linaro.org/gitweb?p=boot/u-boot-linaro-stable.git;a=commitdiff;h=775b2cef2bd9037392cbc9c09fda89f9c2796803

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-05:

Here is the panda ppa .deb int the staging-overlay ppa:

https://code.launchpad.net/~linaro-maintainers/+archive/staging-overlay/+files/u-boot-linaro-omap4-panda_2011.09%2B5362%2B35%2B201110042126~oneiric1_armel.deb

Revision history for this message

Sebastien JAN (sebjan) wrote on 2011-10-05:

Boot tested and verified OPP on 4430 and 4460.

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-05:

Regression tested on panda 4030 and beagle xM

John Rigby (jcrigby) on 2011-10-05

description:	updated
description:	updated

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-06:

debdiff.txt Edit (7.8 KiB, text/plain)

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-06:

uploaded u-boot-linaro_2011.09.6-0ubuntu1 to oneiric-proposed

Revision history for this message

John Rigby (jcrigby) wrote on 2011-10-06:

This upload fixes lp: #867650 as well.

John Rigby (jcrigby) on 2011-10-06

Changed in u-boot-linaro (Ubuntu):
assignee:	nobody → John Rigby (jcrigby)

Ricardo Salveti (rsalveti) on 2011-10-06

Changed in u-boot-linaro (Ubuntu):
importance:	Undecided → High

Revision history for this message

Launchpad Janitor (janitor) wrote on 2011-10-06:

This bug was fixed in the package u-boot-linaro - 2011.09.6-0ubuntu1

---------------
u-boot-linaro (2011.09.6-0ubuntu1) oneiric; urgency=low

  * omap4: reduce default operating point for 4460 devices
    Reduce the operating point for 4460 to OPP100 (MPU at 700MHz)
    (LP: #867670)
      From bug report:
        With both A9 cores loaded 4460 reaches max temperature in about 30s at the
        current operating point of 930MHz. The operating point should be lowered to
        700MHz.
        It appears the panda heats more than I thought (and much more that the blaze),
        and by loading the 2 cores I can quite easily reach max temperature at 920MHz
        (it takes around 30s on my board!).
        At 700MHz, the temperature still increases but much slower. So if the A9 cores
        do not run at 100% all the time we shall be ok.
        So for now, we definitely need this change if we don't want to run with a
        heatsink...
  * mmc: omap: enable high capacity
      Enable high capacity to host capability.
      Fixes eMMC detection on boot from MMC/SD card.
    mmc: omap: config VMMC, MMC1_PBIAS
      Config VMMC voltage to 3V for MMC/SD card slot
      and PBIAS settings needed for OMAP4
    (LP: #867650)
-- John Rigby <email address hidden> Wed, 05 Oct 2011 17:17:34 -0600