Bug 54988

Summary: [C51PV] Garbage on initial Console Screen
Product: xorg Reporter: baldur
Component: Driver/nouveauAssignee: Nouveau Project <nouveau>
Status: RESOLVED DUPLICATE QA Contact: Xorg Project Team <xorg-team>
Severity: critical    
Priority: medium    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg output
none
lspci -vv output
none
/var/log/dmesg from fedora none

Description baldur 2012-09-16 16:06:09 UTC
Created attachment 67247 [details]
dmesg  output

Dear all,

after having bad experiences with nouveau (using fedora 15,16,17) ,
which resulted in an immediate lockup of my old server machine,
i have given noveau another chance to run on a fedora kernel:

Linux version 3.5.3-1.fc17.x86_64 (mockbuild@)


The good is news is - it doesn't lead to immediate lockup of the machine
anymore.

The bad news. It still leads to a scrambled console screen, which does
not contain any useful information.

It seems that there is an "INVALID_CMD" issued by the noveau driver.

Can anybody help me to resolve this problem?
Comment 1 baldur 2012-09-16 16:06:40 UTC
Created attachment 67248 [details]
lspci -vv output
Comment 2 baldur 2012-09-16 16:11:37 UTC
Created attachment 67250 [details]
/var/log/dmesg from fedora

as there are some initial lines missing from my dmesg output, this is what fedora had stored...
Comment 3 Marcin Slusarz 2012-09-16 16:31:48 UTC
does it work if you boot with mem=2G in kernel command line?
Comment 4 baldur 2012-09-16 19:41:48 UTC
yes it works!
(with mem=2G)


But memory is already low on my system, so limiting it to 2G is not an option for me.

This is an 64 bit system. So i am wondering why i have a 32bit (2G?) problem?
Comment 5 Marcin Slusarz 2012-09-16 19:45:48 UTC
Your card has problems addressing memory above 2G.
As a temporary workaround you can apply patch from bug 46557.

*** This bug has been marked as a duplicate of bug 46557 ***
Comment 6 D. Hugh Redelmeier 2012-09-16 19:58:49 UTC
Marcin:

As I mentioned in 46557, I'm not convinced that the problem is hardware.  It could easily be some widening bug in C code.  It smells like sign-extension of a 32 bit quantity that should be zero-extended.  But it could be the truncation of a wider-than-32-bit quantity to 32 bits.  And, of course, it could be hardware.

Why would the 32-bit Linux have no trouble with the identical hardware?
Comment 7 baldur 2012-09-16 20:04:39 UTC
I can add another data point, which indicates it is not the hardware.


This card works "flawless" with the nvidia driver since 4.5 years. It is only my curiosity, why i try nouveau from time to time.

As recompiling the kernel on every new update from fedora is not an option i am going back to the nvidia driver.

But at least i know now how to install a "fresh" fedora (mem=2G), so your help is greatly appreciated!
Comment 8 Marcin Slusarz 2012-09-16 20:38:51 UTC
D. Hugh Redelmeier:
If you can prove it's "widening bug", please do (by fixing it).
Memory used by the kernel in 32-bit mode is allocated in first GB, so you can't hit this bug there.

Dietmar:
Nvidia driver may:
a) init the hardware in a way we don't, fixing this bug
b) workaround it internally by allocating memory in first 2G

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