mainlining shenanigans
Go to file
Ville Syrjälä 6f38123eca drm/i915: Fix rawclk readout for g4x
Turns out our skills in decoding the CLKCFG register weren't good
enough. On this particular elk the answer we got was 400 MHz when
in reality the clock was running at 266 MHz, which then caused us
to program a bogus AUX clock divider that caused all AUX communication
to fail.

Sadly the docs are now in bit heaven, so the fix will have to be based
on empirical evidence. Using another elk machine I was able to frob
the FSB frequency from the BIOS and see how it affects the CLKCFG
register. The machine seesm to use a frequency of 266 MHz by default,
and fortunately it still boot even with the 50% CPU overclock that
we get when we bump the FSB up to 400 MHz.

It turns out the actual FSB frequency and the register have no real
link whatsoever. The register value is based on some straps or something,
but fortunately those too can be configured from the BIOS on this board,
although it doesn't seem to respect the settings 100%. In the end I was
able to derive the following relationship:

BIOS FSB / strap | CLKCFG
-------------------------
200              | 0x2
266              | 0x0
333              | 0x4
400              | 0x4

So only the 200 and 400 MHz cases actually match how we're currently
decoding that register. But as the comment next to some of the defines
says, we have been just guessing anyway.

So let's fix things up so that at least the 266 MHz case will work
correctly as that is actually the setting used by both the buggy
machine and my test machine.

The fact that 333 and 400 MHz BIOS settings result in the same register
value is a little disappointing, as that means we can't tell them apart.
However, according to the gmch datasheet for both elk and ctg 400 Mhz is
not even a supported FSB frequency, so I'm going to make the assumption
that we should decode it as 333 MHz instead.

Cc: stable@vger.kernel.org
Cc: Tomi Sarvela <tomi.p.sarvela@intel.com>
Reported-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100926
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170504181530.6908-1-ville.syrjala@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
2017-05-05 19:49:47 +03:00
arch Linux 4.11-rc7 2017-04-19 11:07:14 +10:00
block blk-mq: Restart a single queue if tag sets are shared 2017-04-07 12:40:09 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-03-31 12:11:32 -07:00
Documentation drm/panel: Changes for v4.12-rc1 2017-04-13 06:17:40 +10:00
drivers drm/i915: Fix rawclk readout for g4x 2017-05-05 19:49:47 +03:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs orangefs: free superblock when mount fails 2017-04-15 09:39:31 -07:00
include main drm pull request for 4.12 kernel 2017-05-03 21:41:35 +02:00
init mm: move mm_percpu_wq initialization earlier 2017-03-31 17:13:30 -07:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel Linux 4.11-rc7 2017-04-19 11:07:14 +10:00
lib Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-04-06 11:57:04 -07:00
mm zsmalloc: expand class bit 2017-04-13 18:24:21 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2017-04-14 10:47:13 -04:00
samples statx: Include a mask for stx_attributes in struct statx 2017-04-03 01:06:00 -04:00
scripts Linux 4.11-rc6 2017-04-11 07:40:42 +10:00
security Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
sound ALSA: x86: Register multiple PCM devices for the LPE audio card 2017-05-03 16:24:00 +03:00
tools Linux 4.11-rc7 2017-04-19 11:07:14 +10:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM Fixes for v4.11-rc6 2017-04-05 16:27:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add Martin Kepplinger's email 2017-04-13 18:24:21 -07:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS Merge tag 'drm-misc-next-fixes-2017-04-20' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-04-21 13:51:59 +10:00
Makefile Linux 4.11-rc7 2017-04-16 13:00:18 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.