From: Jeff Garzik <firstname.lastname@example.org>
To: Alan Cox <email@example.com>
Cc: Patrick Mochel <firstname.lastname@example.org>,
"Grover, Andrew" <email@example.com>,
Benjamin Herrenschmidt <firstname.lastname@example.org>,
Linux Kernel Mailing List <email@example.com>
Subject: Re: Subtle semantic issue with sleep callbacks in drivers
Date: Thu, 17 Apr 2003 10:48:44 -0400 [thread overview]
Message-ID: <20030417144844.GC18749@gtf.org> (raw)
On Thu, Apr 17, 2003 at 02:35:50PM +0100, Alan Cox wrote:
> On Mer, 2003-04-16 at 19:39, Patrick Mochel wrote:
> > I completely agree with Andy. We should not re-POST the video hardware, no
> > matter what. The idea behind ACPI is that the OS takes care of everything,
> > including video save/restore.
> Outside of happyville ivory towers you probably have no choice. Only the
> BIOS knows stuff like the RAM timings, and some windows drivers just use
> the BIOS, others rely on being shipped compiled for the right variant of
> card they came with.
You are exactly right.
The video BIOS on a card often contains information that is found
-nowhere- else. Not in the chip docs. Not in a device driver.
Such information can and does vary from board-to-board, such as RAM
timings, while the chip remains unchanged.
You mention "windows drivers" above... even some Linux X drivers
depend on video BIOS. The S3 Savage XFree86 driver, for example,
uses video BIOS quite heavily unless you tell it not to (or are on
a platform that prevents such).
WRT save and restore, it is certainly possible without video re-POST...
However, support such will require a monumental effort of testing and
debugging for each video board. This monumental effort _will_ include
XFree86 hacking and possibly the additional of some save-n-restore
video drivers, if we do not wish to simply require CONFIG_FBDEV if
CONFIG_SUSPEND is set.
Video re-POST is simply a Real Life(tm) shortcut to that monumental effort.
Jeff, originally an fbdev hacker back in the day...
next prev parent reply other threads:[~2003-04-17 14:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-14 21:09 Subtle semantic issue with sleep callbacks in drivers Grover, Andrew
2003-04-16 18:39 ` Patrick Mochel
2003-04-16 19:36 ` Benjamin Herrenschmidt
2003-04-17 13:35 ` Alan Cox
2003-04-17 14:48 ` Jeff Garzik [this message]
2003-04-17 15:09 ` John Bradford
2003-04-17 15:09 ` Jeff Garzik
2003-04-17 15:47 ` John Bradford
2003-04-17 15:56 ` Jeff Garzik
2003-04-17 16:24 ` Alan Cox
2003-04-18 7:37 ` Greg KH
2003-04-18 7:51 ` John Bradford
2003-04-18 9:10 ` Russell King
2003-04-18 11:18 ` Alan Cox
2003-04-18 11:30 ` Alan Cox
2003-04-29 8:28 ` Pavel Machek
2003-04-17 14:59 ` John Bradford
2003-04-17 15:04 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2003-04-14 19:07 Grover, Andrew
2003-04-14 19:18 ` Benjamin Herrenschmidt
2003-04-14 19:56 ` Alan Cox
2003-04-23 15:34 ` Pavel Machek
2003-04-14 17:09 Grover, Andrew
2003-04-14 17:40 ` Benjamin Herrenschmidt
2003-04-23 15:29 ` Pavel Machek
2003-04-14 10:00 Benjamin Herrenschmidt
2003-04-14 10:11 ` Benjamin Herrenschmidt
2003-04-16 18:31 ` Patrick Mochel
2003-04-16 19:29 ` Benjamin Herrenschmidt
2003-04-23 15:32 ` Pavel Machek
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:
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).