LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Tim Gardner <tim.gardner@canonical.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Suspend to RAM fault in VT when resuming
Date: Mon, 19 Mar 2007 10:15:23 -0600	[thread overview]
Message-ID: <45FEB71B.90406@canonical.com> (raw)
In-Reply-To: <20070319150753.GC1915@elf.ucw.cz>

Pavel Machek wrote:
> On Tue 2007-03-13 19:42:07, Tim Gardner wrote:
>> Pavel Machek wrote:
>>> Hi1
>>>
>>>> I've chased one of the 'Suspend to RAM' resume problems to a specific
>>>> line in drivers/char/vt.c, see attached 2.6.21-rc3 diff with
>>> Has suspend/resume ever worked on that hardware?
>>>
>>>> TRACE_RESUME() instrumentation. The macro scr_writew resolves to '*addr
>>>> = val', which appears to be causing the problem. I've verified that the
>>>> pointer is not NULL, but don't know if its really valid. Its pretty
>>>> tough to tell what is happening, but on a Dell XPS it just hangs. A Dell
>>>> Precision blinks the keyboard lights.
>>> It is possible that video is not initialized at that point, and that
>>> hardware goes seriously unhappy when you access non-existing vga. Does
>>> it resume ok when you completely disable video support? 
>> Resume works on the Dell XPS with the Ubuntu Edgy release
>> Ubuntu-2.6.17-10.25 (2.6.17 plus a zillion fixes). Ubuntu's git tree is
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/bcollins/ubuntu-2.6.git.
>> Ubuntu-2.6.17-8.21 is the first version where resume works, but there
>> are a boatload of changes in ACPI and SW suspend between that and the
>> previous tag Ubuntu-2.6.17-7.20. I don't know what made SW suspend work,
>> but even knowing that won't tell me what broke it again.
>>
>> I've been avoiding the bisect process because it is quite time consuming
>> on my slow machine, there is much branch weirdness, and I'm not that
>> good with git. I thought if I narrowed the failure down to a small chunk
>> of code in 2.6.21-rc3, then the answer might be obvious. No such luck, huh?
>>
>> This crash behaves like the video memory space has become unmapped. Is
>> that possible?
> 
> That seems improbable. It is physical ram, we do not unmap that..
> 

The machine _has_ just come out of BIOS ACPI space. Perhaps PCI
resources for video are hosed. All I can tell for sure is that this one
line appears to cause some kind of crash. I'm working on finding some
1394 resources to see if I can nail this one.

-- 
Tim Gardner tim.gardner@ubuntu.com

  reply	other threads:[~2007-03-19 16:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-13 20:30 Tim Gardner
2007-03-13 21:24 ` Pavel Machek
2007-03-14  1:42   ` Tim Gardner
2007-03-19 15:07     ` Pavel Machek
2007-03-19 16:15       ` Tim Gardner [this message]
2007-03-19 20:45         ` Pavel Machek

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=45FEB71B.90406@canonical.com \
    --to=tim.gardner@canonical.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pavel@ucw.cz \
    --subject='Re: Suspend to RAM fault in VT when resuming' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).