Bug 103261 - READ LOG DMA EXT failed, trying unqueued
Summary: READ LOG DMA EXT failed, trying unqueued
Status: NEW
Alias: None
Product: IO/Storage
Classification: Unclassified
Component: Serial ATA (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Tejun Heo
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-08-21 20:48 UTC by KernelBug
Modified: 2015-08-25 00:35 UTC (History)
1 user (show)

See Also:
Kernel Version: 4.1.6
Tree: Mainline
Regression: No


Attachments

Description KernelBug 2015-08-21 20:48:27 UTC
I filed this bug report about 'failed to get NCQ Send/Recv Log Emask 0x1';

https://bugzilla.kernel.org/show_bug.cgi?id=72341

Now I see this in my DMESG for 4.1.6;

READ LOG DMA EXT failed, trying unqueued

I don't know if there is a relation here, meaning, unsupported device with my Samsung 850 Pro 128GB SSD?
Comment 1 David Milburn 2015-08-21 21:00:27 UTC
Hi,

I think it is the firmware, a similiar question came up on a SAMSUNG SSD 840 EVO.

Reporter updated firmware and the failure disappeared.

Here is link to upstream discussion, thanks.

http://www.spinics.net/lists/linux-ide/msg50938.html
Comment 2 KernelBug 2015-08-21 21:04:34 UTC
The 850 Pro does not have any firmware updates at this time...

In the meantime I'm wondering if I'm going to run into any problems?

Found this patch, not sure if I should apply it;

https://lkml.org/lkml/2015/5/19/451
Comment 3 David Milburn 2015-08-21 21:37:57 UTC
(In reply to KernelBug from comment #2)
> The 850 Pro does not have any firmware updates at this time...
> 
> In the meantime I'm wondering if I'm going to run into any problems?

I don't think so, it should be falling back to ATA_CMD_READ_LOG_EXT.

> 
> Found this patch, not sure if I should apply it;
> 
> https://lkml.org/lkml/2015/5/19/451

You can, it was committed. Thanks.

commit eab6ee1ce3c4678224d70338134f7a02005768cb
    libata: Fix regression when the NCQ Send and Receive log page is absent
Comment 4 KernelBug 2015-08-21 21:52:35 UTC
Commited, what do you mean? It's going to end up in the kernel later?
Comment 5 KernelBug 2015-08-22 02:03:17 UTC
It seems to of been applied already, I'm using 4.1.6

So if the patch has already been added in, is it stil normal to get this msg?

thanks
Comment 6 KernelBug 2015-08-24 01:11:36 UTC
Is this some hardware error that will cause problems, or is this a failure to read a log?

thanks
Comment 7 David Milburn 2015-08-24 14:47:44 UTC
Hi,

Even with the patch applied (Comment#3), it won't get rid of the message,
but it will keep you from spinning in "READ LOG DMA EXT failed, trying
unqueued", I don't think it will cause you any more errors. The problem is
the drive advertises that it supports the DMA variant of READ LOG EXT, but
it really doesn't so driver falls back. Thanks.
Comment 8 KernelBug 2015-08-25 00:35:28 UTC
Ok thanks...

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