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Bug 1114653

Summary: No display with MGA G550
Product: Red Hat Enterprise Linux 6 Reporter: Martin <mholec>
Component: kernelAssignee: Adam Jackson <ajax>
kernel sub component: Graphics QA Contact: Desktop QE <desktop-qa-list>
Status: CLOSED WONTFIX Docs Contact:
Severity: urgent    
Priority: unspecified CC: tlavigne, tpelka
Version: 6.6Keywords: Reopened
Target Milestone: rc   
Target Release: 6.5   
Hardware: Unspecified   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-12-06 12:17:55 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
Xorg.0.log
none
dmesg
none
Without config file with suggested options
none
With config file with suggested options none

Description Martin 2014-06-30 14:42:57 UTC
Created attachment 913430 [details]
Xorg.0.log

Version-Release number of selected component (if applicable):
MGA G550 AGP (PCI-e variant) [102b:2527]
kernel-2.6.32-482.el6

Steps to Reproduce: 
Boot


Actual results: 
Xorg doesn't start. I can switch to VT, attached Xorg.0.log and dmesg logs.
Same result when booting with "nomodeset" parameter.

Expected results:
Xorg starts with GDM.

Comment 2 Martin 2014-06-30 15:00:54 UTC
Created attachment 913441 [details]
dmesg

Comment 3 Martin 2014-06-30 15:02:07 UTC
According to tpelka, this bug is a regression.

Comment 4 Adam Jackson 2014-07-02 14:27:03 UTC
(In reply to Martin Holec from comment #0)

> Actual results: 
> Xorg doesn't start. I can switch to VT, attached Xorg.0.log and dmesg logs.
> Same result when booting with "nomodeset" parameter.

Not actually the case.  The log shows clients connecting and disconnecting.  X is started, it's just not showing anything.

I think I know what this is though.  Does it work if you use this for an xorg.conf:

Section "Device"
  Identifier "mga"
  Driver "mga"
  Option "NoAccel"
  Option "ShadowFB" "off"
EndSection

Comment 6 Milan Barta 2014-07-18 11:12:34 UTC
Hi Adam, when trying to reproduce this bug, the X server started just fine with no additional configuration needed. However, adding suggested options to the config file eliminated these error messages:

(EE) open /dev/dri/card0: No such file or directory 
(EE) open /dev/fb0: No such device

So I suggest the options should be default for this card.

Just a few notes from testing the card:
1. I wasn't able to get any signal for my display if the dvi2vga reduction wasn't used
2. With multidisplay setup there is only mirroring possible

Logs follow.

Comment 7 Milan Barta 2014-07-18 11:13:33 UTC
Created attachment 919054 [details]
Without config file with suggested options

Comment 8 Milan Barta 2014-07-18 11:14:02 UTC
Created attachment 919055 [details]
With config file with suggested options

Comment 9 Adam Jackson 2014-07-22 16:27:50 UTC
(In reply to Milan Barta from comment #6)
> Hi Adam, when trying to reproduce this bug, the X server started just fine
> with no additional configuration needed. However, adding suggested options
> to the config file eliminated these error messages:
> 
> (EE) open /dev/dri/card0: No such file or directory 
> (EE) open /dev/fb0: No such device
> 
> So I suggest the options should be default for this card.

It doesn't quite work like that, unfortunately.  Those EE messages aren't being generated by the mga driver, they're being generated by the fbdev and modesetting drivers (which are general-purpose fallback drivers) in their probe paths; that they print those messages is because they are correctly discovering that they should not bind to the device.

Specifying a config file disables this probe logic entirely; the server instead uses the driver you name in the config file, on the assumption that you knew what you were asking for.  So it's not the config file options that "fix" it, it's the config file itself.

> Just a few notes from testing the card:
> 1. I wasn't able to get any signal for my display if the dvi2vga reduction
> wasn't used

Really?  Which version of the mga driver were you testing?  There was a fix for this upstream and I'd thought we'd included it.

> 2. With multidisplay setup there is only mirroring possible

That's expected, multihead isn't entirely supported on G550 cards.

Comment 10 Milan Barta 2014-07-24 12:55:34 UTC
(In reply to Adam Jackson from comment #9)
> ...
> Really?  Which version of the mga driver were you testing?  There was a fix
> for this upstream and I'd thought we'd included it.

I tested this on latest RHEL 6.6, xorg-x11-drv-mga-1.6.3-2.el6.

The thing is I thought it might have been a hardware issue, since I recall there was no signal from the card even when booting (starting with BIOS messages and Grub screen) without the dvi2vga reduction.

Comment 11 Adam Jackson 2014-07-31 14:14:38 UTC
(In reply to Milan Barta from comment #10)

> The thing is I thought it might have been a hardware issue, since I recall
> there was no signal from the card even when booting (starting with BIOS
> messages and Grub screen) without the dvi2vga reduction.

Mmm.  The G550 is a weird beast, the two DVI ports aren't identically functional and the BIOS doesn't necessarily initialize them both, IIRC.  So maybe that's unfortunate, but may not mean it's something we could fix even if we wanted to.

This is marked as a regression, which given the discussion here I'm not sure is actually the case.  Can we get the text matrix from booting this card with both 6.5 and 6.6, testing both DVI ports, each both with and without a DVI->VGA converter?  That should be enough to determine whether this is actually a regression.  (The DVI functionality still might not be working perfectly, but that's not a bug we were going out of our way to fix in 6.6, so while it might still be something we should fix it wouldn't be a 6.6 blocker.)

Comment 12 Tomas Pelka 2014-07-31 19:20:09 UTC
Reseting need_info to mbarta since Martin will be not in the office before beginning of September.

Comment 13 Milan Barta 2014-08-04 08:21:01 UTC
Hi Adam,
I tested the card on both RHEL6.5 and RHEL6.6 and the result is that the DVI output simply doesn't send any signal unless the dvi2vga converter is used in any case.

Looks more like a hardware issue to me.

Anyway, back to the original report, can I do anything to help you find out more about the original issue? With the converter in use, I couldn't reproduce though, Xorg started just fine each time.

Comment 14 Adam Jackson 2014-08-05 14:52:16 UTC
(In reply to Milan Barta from comment #13)
> Hi Adam,
> I tested the card on both RHEL6.5 and RHEL6.6 and the result is that the DVI
> output simply doesn't send any signal unless the dvi2vga converter is used
> in any case.

Sounds like it's not a regression then.

> Anyway, back to the original report, can I do anything to help you find out
> more about the original issue? With the converter in use, I couldn't
> reproduce though, Xorg started just fine each time.

There's nothing additional I need there, no.  DVI setup on G400/450/550 has been a known issue for a long time.  It's unfortunate that the update in 6.6 didn't fix it, but it's not something we were trying to fix.

Comment 17 Jan Kurik 2017-12-06 12:17:55 UTC
Red Hat Enterprise Linux 6 is in the Production 3 Phase. During the Production 3 Phase, Critical impact Security Advisories (RHSAs) and selected Urgent Priority Bug Fix Advisories (RHBAs) may be released as they become available.

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This issue does not meet the inclusion criteria for the Production 3 Phase and will be marked as CLOSED/WONTFIX. If this remains a critical requirement, please contact Red Hat Customer Support to request a re-evaluation of the issue, citing a clear business justification. Note that a strong business justification will be required for re-evaluation. Red Hat Customer Support can be contacted via the Red Hat Customer Portal at the following URL:

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