Bug 5817 - hotkey switching from LFT to CRT gives 'dirty' crt output on i915GM
Summary: hotkey switching from LFT to CRT gives 'dirty' crt output on i915GM
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: 7.0.0
Hardware: x86 (IA32) Linux (All)
: medium enhancement
Assignee: Alan Hourihane
QA Contact: Xorg Project Team
Keywords: patch
Depends on:
Reported: 2006-02-06 08:43 UTC by Carl Michal
Modified: 2007-05-11 02:18 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

Patch for CloneOnHotKey option (2.83 KB, patch)
2006-03-03 07:00 UTC, Carl Michal
no flags Details | Splinter Review

Description Carl Michal 2006-02-06 08:43:11 UTC
On a Dell 630m laptop with an i915GM video card, hotkey-switching (Fn-F8) does
do what it is supposed to do: switching from LFP -> CRT -> LFP & CRT simultaneously.

However, when both the LFP & CRT are on simultaneously, the CRT output is
unusable.  The display wobbles back and forth and makes you feel like the
monitor is about to blow up.

From the i855crt documentation (http://sourceforge.net/projects/i855crt) it
appears that this is due to both outputs being enabled from the same pipe. 
Using the i855crt userspace program does turn on the crt cleanly (i810switch has
the same problem as the hotkey).

Using the clone option in xorg.conf also turns on the crt cleanly - but when
operating on batteries it would be nice to not have the second output turned on
all the time.

It would clearly be best if the hotkey did the right thing on its own.  If there
is some reason not to have it use the second pipe by default on a hot-key
switch, maybe there could be an xorg-option like:  CloneOnHotKey "on" ?

Otherwise this card works great for me:  no problems with suspend/resume and
dual head (xinerama and two separate screens) works fine.  The 855resolution
tool is needed to get the widescreen display working properly.  

Thanks for the nice work.
Comment 1 Alan Hourihane 2006-02-10 03:25:04 UTC
Yes, I could definately add a CloneOnHotkey option. I'll try and do this next week.
Comment 2 Carl Michal 2006-02-16 09:34:44 UTC
That would be excellent.  I'd be happy to test.
Comment 3 Alan Hourihane 2006-02-18 04:35:55 UTC
Before I add it, you should be able to get similar behaviour with the clone
option  already. Try this...

Even though the second screen will be on at startup, if you hotkey, it should
cycle through the LFP, CRT and LFP+CRT for clone.

Comment 4 Carl Michal 2006-02-18 12:19:43 UTC
Yes, when Clone is set in xorg.conf, it does cycle properly.  I guess the only
difference CloneOnHotKey option will have from Clone is to start up in the LFP
state, but the behaviour otherwise should be identical.

There is one other somewhat related issue - this laptop has a 1280x768
widescreen,  if I don't remember to reset the resolution before switching it
makes the crt very unhappy, but that's probably a problem for another day.
Comment 5 Carl Michal 2006-03-03 07:00:49 UTC
Created attachment 4802 [details] [review]
Patch for CloneOnHotKey option

I've given this a try on my own.  The attached patch works for me...

Any chance this could get officially added?
Comment 6 Daniel Stone 2007-02-27 01:30:18 UTC
Sorry about the phenomenal bug spam, guys.  Adding xorg-team@ to the QA contact so bugs don't get lost in future.
Comment 7 Gordon Jin 2007-03-14 19:24:58 UTC
The bug priority was upgraded (P2->high) with the bugzilla configuration change.
I'm Changing the priority back to the normal one.
Sorry for the spam.
Comment 8 Alan Hourihane 2007-05-11 02:18:03 UTC
Closing. Please use the new 2.0 driver.

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