linux-kernel - Re: Samsung N130 ATA exception after 5min uptime -- Phoenix FailSafe issue?

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Date:	Sat, 28 Nov 2009 14:30:38 -0600
From:	Robert Hancock <hancockrwd@...il.com>
To:	Greg KH <greg@...ah.com>
CC:	Johannes Stezenbach <js@...21.net>,
	Mikhail Malygin <mmalygin@....de>,
	Hans Werner <hwerner4@....de>, Tejun Heo <tj@...nel.org>,
	Thomas Renninger <trenn@...e.de>, linux-kernel@...r.kernel.org
Subject: Re: Samsung N130 ATA exception after 5min uptime -- Phoenix   FailSafe
 issue?

On 11/28/2009 01:19 PM, Greg KH wrote:
> On Thu, Nov 26, 2009 at 05:42:12PM +0100, Johannes Stezenbach wrote:
>> Hi,
>>
>> I'm refering to
>> http://bugzilla.kernel.org/show_bug.cgi?id=14314
>> and I still have this issue on a N130 with latest BIOS (05CM),
>> running kernel 2.6.32-rc8 + wireless-testing.
>>
>> BIOS Information
>>          Vendor: Phoenix Technologies Ltd.
>>          Version: 05CM.M011.20091013.JIP
>>          Release Date: 10/13/2009
>>          Address: 0xE6300
>>          Runtime Size: 105728 bytes
>>          ROM Size: 2048 kB
>>          Characteristics:
>>                  ISA is supported
>>                  PCI is supported
>>                  PNP is supported
>>                  BIOS is upgradeable
>>                  BIOS shadowing is allowed
>>                  ESCD support is available
>>                  ACPI is supported
>>                  USB legacy is supported
>>                  Smart battery is supported
>>                  BIOS boot specification is supported
>>                  Targeted content distribution is supported
>>          BIOS Revision: 5.0
>>
>> Around 5min after boot or resume if generates the following error:
>>
>> [  302.364174] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
>> [  302.364201] ata1.00: failed command: WRITE DMA
>> [  302.364234] ata1.00: cmd ca/00:08:f7:01:1a/00:00:00:00:00/e0 tag 0 dma 4096 out
>> [  302.364241]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
>> [  302.364257] ata1.00: status: { DRDY }
>> [  307.408107] ata1: link is slow to respond, please be patient (ready=0)
>> [  312.392109] ata1: device not ready (errno=-16), forcing hardreset
>> [  312.392138] ata1: soft resetting link
>> [  312.574482] ata1.00: configured for UDMA/133
>> [  312.574506] ata1.00: device reported invalid CHS sector 0
>> [  312.574542] ata1: EH complete
>
> This is because after 5 minutes, the BIOS implements C states in the
> processor, which causes a "hic-up" in userspace.  Everything should be
> fine after this, and most importantly, the power usage drops by a few
> watts, which is most important.

Why does this "hiccup" seem to cause interrupts to get lost? This would 
cause an up to 30-second stall in disk I/O.

>
>> This also happens when booting with rdinit=/bin/sh, i.e. only running busybox sh
>> inside initrd.  The error then appears when accessing the disk after the 5min
>> period with dd if=/dev/sda of=/dev/null count=10000.
>
> Yup, see above for why.
>
> Samsung does this to make booting their BIOS faster.

Ugh.. Seriously?

>
>> The link in comment #14 is dead but eventually I found
>> http://download.opensuse.org/repositories/Moblin:/Base/openSUSE_11.1/src/kernel-source-2.6.31.6-37.1.src.rpm
>> which contains the attached patch with a samsung_laptop driver.
>>
>> I think it is weird that the Samsung BIOS has a special "SECLINUX" mode,
>> but anyway the samsung_laptop driver works (the backlight control via ACPI
>> also works with the 05CM BIOS, though).
>
> Yes, but Samsung does not support ACPI at this time, even though it is
> in their latest bios versions (experimental stuff, needed for Windows 7
> mode or something...)

ACPI support would seem much preferable to implementing power management 
with such strange proprietary hacks..

>
> And yes, a "special" linux mode is weird, but at least they gave us
> something that works :)
>
>> However, it does not prevent the ATA exception.
>
> Yup, it's not an issue though.
>
>> (Side note about backlight level 0: I noticed that in Windows when you
>> set the backlight to the lowest level, after a minute of inactivity
>> the screen would dim one level more. Stupid -- why not allow the user
>> to choose that level manually?)
>
> Talk to samsung about this.  There is one more lower level the BIOS can
> go to, which is what Windows does here.  Samsung doesn't want Linux to
> use that mode at this time.  It only saves a bit less than .1W, so it's
> not that big of a deal.
>
> Glad it's all working for you now.
>
> greg k-h

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