Fwd: proposal for important kernel patch

[Tim Gardner]

-------- Forwarded Message --------
Subject: proposal for important kernel patch
Date: Wed, 20 May 2015 09:04:54 -0000
From: Andrea Bravetti <andreabravetti at gmail.com>
Reply-To: Andrea Bravetti <andreabravetti at gmail.com>
To: Tim Gardner <tim.gardner at canonical.com>

I don't know how to propose an important kernel patch, so I ask you.

The first patch I would like to bring to your attention is this:

--- drivers/ata/libata-core.c   2015-05-11 18:49:06.699847395 +0200
+++ drivers/ata/libata-core.c   2015-05-11 18:52:23.402510885 +0200
@@ -4246,6 +4246,8 @@
         { "WDC WD3000JD-*",             NULL,
ATA_HORKAGE_WD_BROKEN_LPM },
         { "WDC WD3200JD-*",             NULL,
ATA_HORKAGE_WD_BROKEN_LPM },
+       { "Samsung SSD 840*",           NULL,   ATA_HORKAGE_NO_NCQ_TRIM,
},
+
         /* End Marker */
         { }
  };

Why is explained here:
https://bugs.launchpad.net/ubuntu/+source/fstrim/+bug/1449005

Whitout this patch, or "libata.force=noncq", the Samsung SSD 840 is
unusable with new firmware EXT0DB6Q: We lost a working day for this
problem.

The second one is a change in default kernel configuration:

--- .config     2015-05-20 10:28:41.709948652 +0200
+++ .config     2015-05-20 09:23:13.332909672 +0200
@@ -635,5 +635,5 @@
  #
  CONFIG_X86_PCC_CPUFREQ=y
-CONFIG_X86_ACPI_CPUFREQ=y
+CONFIG_X86_ACPI_CPUFREQ=m
  CONFIG_X86_ACPI_CPUFREQ_CPB=y
  CONFIG_X86_POWERNOW_K8=m

"acpi_cpufreq" should be built always as module and NEVER builtin
because it prevent phc-linux being loaded, and also any other
acpi_cpufreq replacement provided by the vendor if any.

"phc-linux" is very important if you need to downvolt some cpu.

Since I can't see any problem building it as a module and it should not
cause any regression it should be made even on 14.04 LTS, and for any
future release.

You can read about linux-phc here: http://www.linux-phc.org/forum

Also having linux-phc in the default kernel would be great but it may
need some work.

It's important, especially for some ThinkPad notebook like the Edge 15
0301-J4G that hang frequently over 100C because of buggy voltage
regulation, even new, clean fan, etc...

Not asking to fix in the mainstream kernel somethink so specific and
hardware bug related, but please please please don't force anyone has
this problem to rebuild a custom kernel because it's very annoying, just
build acpi_cpufreq as module and not builtin.

sincerely,
Andrea
-- 
This message was sent from Launchpad by
Andrea Bravetti (https://launchpad.net/~andreabravetti)
using the "Contact this team's admins" link on the Ubuntu Kernel Team team
page (https://launchpad.net/~ubuntu-kernel-team).
For more information see
https://help.launchpad.net/YourAccount/ContactingPeople