commit 00ca0de02f upstream.
When we update the DSCR either via emulation of mtspr(DSCR) or via
a change to dscr_default in sysfs we don't update thread.dscr.
We will eventually update it at context switch time but there is
a period where thread.dscr is incorrect.
If we fork at this point we will copy the old value of thread.dscr
into the child. To avoid this, always keep thread.dscr in sync with
reality.
This issue was found with the following testcase:
http://ozlabs.org/~anton/junkcode/dscr_inherit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1b6ca2a6fe upstream.
Writing to dscr_default in sysfs doesn't actually change the DSCR -
we rely on a context switch on each CPU to do the work. There is no
guarantee we will get a context switch in a reasonable amount of time
so fire off an IPI to force an immediate change.
This issue was found with the following test case:
http://ozlabs.org/~anton/junkcode/dscr_explicit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 50ce5c0683 upstream.
This patch (as1636) is a partial workaround for a hardware bug
affecting OHCI controllers by NVIDIA at least, maybe others too. When
the controller retires a Transfer Descriptor, it is supposed to add
the TD onto the Done Queue. But sometimes this doesn't happen, with
the result that ohci-hcd never realizes the corresponding transfer has
finished. Symptoms can vary; a typical result is that USB audio stops
working after a while.
The patch works around the problem by recognizing that TDs are always
processed in order. Therefore, if a later TD is found on the Done
Queue than all the earlier TDs for the same endpoint must be finished
as well.
Unfortunately this won't solve the problem in cases where the missing
TD is the last one in the endpoint's queue. A complete fix would
require a signficant amount of change to the driver.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a6b5e88c0e upstream.
During resume from system suspend the 'data' field of
struct pnp_dev in pnpacpi_set_resources() may be a stale pointer,
due to removal of the associated ACPI device node object in the
previous suspend-resume cycle. This happens, for example, if a
dockable machine is booted in the docking station and then suspended
and resumed and suspended again. If that happens,
pnpacpi_build_resource_template() called from pnpacpi_set_resources()
attempts to use that pointer and crashes.
However, pnpacpi_set_resources() actually checks the device's ACPI
handle, attempts to find the ACPI device node object attached to it
and returns an error code if that fails, so in fact it knows what the
correct value of dev->data should be. Use this observation to update
dev->data with the correct value if necessary and dump a call trace
if that's the case (once).
We still need to fix the root cause of this issue, but preventing
systems from crashing because of it is an improvement too.
Reported-and-tested-by: Zdenek Kabelac <zdenek.kabelac@gmail.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=51071
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4000e62615 upstream.
Add a quirk to correctly report battery capacity on 2010 and 2011
Lenovo Thinkpad models.
The affected models that I tested (x201, t410, t410s, and x220)
exhibit a problem where, when battery capacity reporting unit is mAh,
the values being reported are wrong. Pre-2010 and 2012 models appear
to always report in mWh and are thus unaffected. Also, in mid-2012
Lenovo issued a BIOS update for the 2011 models that fixes the issue
(tested on x220 with a post-1.29 BIOS). No such update is available
for the 2010 models, so those still need this patch.
Problem description: for some reason, the affected Thinkpads switch
the reporting unit between mAh and mWh; generally, mAh is used when a
laptop is plugged in and mWh when it's unplugged, although a
suspend/resume or rmmod/modprobe is needed for the switch to take
effect. The values reported in mAh are *always* wrong. This does
not appear to be a kernel regression; I believe that the values were
never reported correctly. I tested back to kernel 2.6.34, with
multiple machines and BIOS versions.
Simply plugging a laptop into mains before turning it on is enough to
reproduce the problem. Here's a sample /proc/acpi/battery/BAT0/info
from Thinkpad x220 (before a BIOS update) with a 4-cell battery:
present: yes
design capacity: 2886 mAh
last full capacity: 2909 mAh
battery technology: rechargeable
design voltage: 14800 mV
design capacity warning: 145 mAh
design capacity low: 13 mAh
cycle count: 0
capacity granularity 1: 1 mAh
capacity granularity 2: 1 mAh
model number: 42T4899
serial number: 21064
battery type: LION
OEM info: SANYO
Once the laptop switches the unit to mWh (unplug from mains, suspend,
resume), the output changes to:
present: yes
design capacity: 28860 mWh
last full capacity: 29090 mWh
battery technology: rechargeable
design voltage: 14800 mV
design capacity warning: 1454 mWh
design capacity low: 200 mWh
cycle count: 0
capacity granularity 1: 1 mWh
capacity granularity 2: 1 mWh
model number: 42T4899
serial number: 21064
battery type: LION
OEM info: SANYO
Can you see how the values for "design capacity", etc., differ by a
factor of 10 instead of 14.8 (the design voltage of this battery)?
On the battery itself it says: 14.8V, 1.95Ah, 29Wh, so clearly the
values reported in mWh are correct and the ones in mAh are not.
My guess is that this problem has been around ever since those
machines were released, but because the most common Thinkpad
batteries are rated at 10.8V, the error (8%) is small enough that it
simply hasn't been noticed or at least nobody could be bothered to
look into it.
My patch works around the problem by adjusting the incorrectly
reported mAh values by "10000 / design_voltage". The patch also has
code to figure out if it should be activated or not. It only
activates on Lenovo Thinkpads, only when the unit is mAh, and, as an
extra precaution, only when the battery capacity reported through
ACPI does not match what is reported through DMI (I've never
encountered a machine where the first two conditions would be true
but the last would not, but better safe than sorry).
I've been using this patch for close to a year on several systems
without any problems.
References: https://bugzilla.kernel.org/show_bug.cgi?id=41062
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
