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  1. 20 8月, 2011 3 次提交
    • P
      OMAP4: clock: re-enable previous clockdomain enable/disable sequence · 9c5f5601
      由 Paul Walmsley 提交于 
      After commit 665d0013 ("OMAP2+: hwmod:
Follow the recommended PRCM module enable sequence"), device drivers
for OMAP IP blocks that do not use runtime PM can cause oopses or
kernel instability[1][2].

This is because those non-runtime PM drivers do not use the hwmod
code, which implements the correct IP block enable and disable
sequence.

Several options for dealing with this problem have been proposed:

1. Add a new field to the OMAP struct clk to mark clocks that are
   currently used by non-runtime PM drivers.  Modify the clock code to
   use the old clockdomain sequence for these marked clocks.  As
   drivers are converted to use runtime PM, remove the annotation from
   the clocks.

2. Similar to #1, but associate the flag with the struct omap_clk
   instead.

3. Add IDLEST wait support to the OMAP4 clock code, similar to the way
   it is implemented for OMAP2/3, and enable it in each struct clk
   currently used by non-runtime PM drivers.  As drivers are converted
   to use runtime PM, remove the annotation from the clocks.

4. Do nothing; leave the problem to those responsible for the
   unconverted drivers.

5. Re-enable clock-based clockdomain control in the OMAP4 clock code.
   This would revert back to the behavior of Linux 3.0, simply with a
   slightly longer module enable/disable latency.

Unfortunately, no approach seemed particularly good.  Options 1
through 3 seemed unwise due to the following reasons:

A. The OMAP struct clks are intended primarily to describe hardware
   clock nodes, and the intention is that no driver-specific data
   should be stored there (applies to #1)

B. The resulting patch would have been quite large for the -rc series
   (applies to #1, #2, #3)

C. The patch would have been a new, yet temporary hack; and similar fixes
   have drawn negative comments in the recent past (see for example [3])

Option 4 is undesirable because commit
665d0013 ("OMAP2+: hwmod: Follow the
recommended PRCM module enable sequence") has resulted in a less
stable kernel; and kernel stability is more important than OMAP4 power
management.

Option 5 is the approach taken in this patch.  This seemed to be the
least intrusive approach for 3.1-rc.

The approach in this patch was originally proposed by Ohad Ben-Cohen
<ohad@wizery.com>.  I'm simply writing the commit message and passing
it along.

...

Thanks to Luciano Coelho <coelho@ti.com> for reporting the problem.
Thanks to Ohad Ben-Cohen <ohad@wizery.com> for tracking the problem
down, generating a temporary workaround, and proposing a patch to deal
with the problem.  Thanks to Rajendra Nayak <rnayak@ti.com> for
proposing another patch to deal with the problem.  Thanks to Felipe
Balbi <balbi@ti.com> for comments.

1. Coelho, Luciano <coelho@ti.com>.  _Re: Oops on ehci_hcd when
   booting 3.0.0-rc2 on panda_.  Tue, 09 Aug 2011 14:26:08 +0300.
   Posted to the <linux-omap@vger.kernel.org> mailing list.  Available
   from (among others)
   http://www.spinics.net/linux/lists/linux-omap/msg55213.html

2. Munegowda, Keshava <keshava_mgowda@ti.com>. _Re: Oops on ehci_hcd
   when booting 3.0.0-rc2 on panda_.  Thu, 11 Aug 2011 13:51:05 +0530.
   Posted to the <linux-omap@vger.kernel.org> mailing list.  Available
   from (among others)
   http://www.spinics.net/linux/lists/linux-omap/msg55371.html

3. King, Russell <linux@arm.linux.org.uk>.  _Re: [PATCH 5/8] OMAP4:
   PM: TEMP: Prevent l3init from idling/force sleep_.  Thu, 23 Jun
   2011 16:22:49 +0100.  Posted to the <linux-omap@vger.kernel.org>
   mailing list.  Available from (among others)
   http://www.mail-archive.com/linux-omap@vger.kernel.org/msg51392.htmlSigned-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Luciano Coelho <coelho@ti.com>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
      9c5f5601
    • L
      Merge branch 'for-linus' of git://git.kernel.dk/linux-block · 5ccc3874
      由 Linus Torvalds 提交于 
      * 'for-linus' of git://git.kernel.dk/linux-block: (23 commits)
  Revert "cfq: Remove special treatment for metadata rqs."
  block: fix flush machinery for stacking drivers with differring flush flags
  block: improve rq_affinity placement
  blktrace: add FLUSH/FUA support
  Move some REQ flags to the common bio/request area
  allow blk_flush_policy to return REQ_FSEQ_DATA independent of *FLUSH
  xen/blkback: Make description more obvious.
  cfq-iosched: Add documentation about idling
  block: Make rq_affinity = 1 work as expected
  block: swim3: fix unterminated of_device_id table
  block/genhd.c: remove useless cast in diskstats_show()
  drivers/cdrom/cdrom.c: relax check on dvd manufacturer value
  drivers/block/drbd/drbd_nl.c: use bitmap_parse instead of __bitmap_parse
  bsg-lib: add module.h include
  cfq-iosched: Reduce linked group count upon group destruction
  blk-throttle: correctly determine sync bio
  loop: fix deadlock when sysfs and LOOP_CLR_FD race against each other
  loop: add BLK_DEV_LOOP_MIN_COUNT=%i to allow distros 0 pre-allocated loop devices
  loop: add management interface for on-demand device allocation
  loop: replace linked list of allocated devices with an idr index
  ...
      5ccc3874
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 · 0c3bef61
      由 Linus Torvalds 提交于 
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  PCI: OF: Don't crash when bridge parent is NULL.
  PCI: export pcie_bus_configure_settings symbol
  PCI: code and comments cleanup
  PCI: make cardbus-bridge resources optional
  PCI: make SRIOV resources optional
  PCI : ability to relocate assigned pci-resources
  PCI: honor child buses add_size in hot plug configuration
  PCI: Set PCI-E Max Payload Size on fabric
      0c3bef61
  3. 19 8月, 2011 18 次提交
  5. 18 8月, 2011 15 次提交
  7. 17 8月, 2011 4 次提交