Go Back   nV News Forums > Linux Support Forums > NVIDIA Linux

Newegg Daily Deals

Reply
 
Thread Tools
Old 10-12-11, 02:35 PM   #1
skohrs
Registered User
 
Join Date: Oct 2011
Posts: 2
Default Override DPCD information

Greetings,

I'm trying to solve a problem where a Quadro NVS 450 cannot determine the proper DisplayPort link rate, lane count, and pixel clock speed, when the monitors are turned off. Is there a way to override these parameters in the xorg.conf?

Here is a snippet from the Xorg log when the monitors are off:

Code:
(WW) Oct 11 15:39:28 NVIDIA(GPU-0): DFP-2: Failed to read DPCD
(II) Oct 11 15:39:28 NVIDIA(GPU-0):     Maximum link rate:   1.62 Gbps per lane
(II) Oct 11 15:39:28 NVIDIA(GPU-0):     Maximum lane count:  1
(II) Oct 11 15:39:28 NVIDIA(GPU-0):     Maximum pixel clock: 71.287 MHz

Here is a snippet from the Xorg log when the monitors are on:

Code:
(II) Oct 11 15:52:53 NVIDIA(GPU-0): DFP-2: DisplayPort revision 1.1
(II) Oct 11 15:52:53 NVIDIA(GPU-0):     Maximum link rate:   2.70 Gbps per lane
(II) Oct 11 15:52:53 NVIDIA(GPU-0):     Maximum lane count:  4
(II) Oct 11 15:52:53 NVIDIA(GPU-0):     Maximum pixel clock: 475.248 MHz

Thank you.


PS I'm receiving the following error while trying to upload a nvidia-bug-report:

nvidia-bug-report.log.gz:
Your file of 160.5 KB bytes exceeds the forum's limit of 146.9 KB for this filetype.
Attached Files
File Type: txt xorg.conf.txt (6.6 KB, 79 views)
skohrs is offline   Reply With Quote
Old 10-12-11, 03:21 PM   #2
AaronP
NVIDIA Corporation
 
AaronP's Avatar
 
Join Date: Mar 2005
Posts: 2,487
Default Re: Override DPCD information

I'm afraid not, sorry. Is there any way you can make sure the monitors are on before trying to start X?
AaronP is offline   Reply With Quote
Old 10-12-11, 04:09 PM   #3
AaronP
NVIDIA Corporation
 
AaronP's Avatar
 
Join Date: Mar 2005
Posts: 2,487
Default Re: Override DPCD information

Actually, I take that back: there's a "NoDisplayPortBandwidthCheck" mode validation override. That completely ignores DisplayPort bandwidth constraints, but since your monitors negotiate the maximum bandwidth when they're on anyway, that shouldn't matter.

See ftp://download.nvidia.com/XFree86/Li...ModeValidation
AaronP is offline   Reply With Quote
Old 10-12-11, 04:25 PM   #4
skohrs
Registered User
 
Join Date: Oct 2011
Posts: 2
Default Re: Override DPCD information

Thanks for the information. I am using the "NoDisplayPortBandwidthCheck" mode validation override, but it computes the values way too low. Do you happen to know how those values are calculated or are they hardcoded somewhere?
skohrs is offline   Reply With Quote
Old 10-17-11, 03:09 PM   #5
AaronP
NVIDIA Corporation
 
AaronP's Avatar
 
Join Date: Mar 2005
Posts: 2,487
Default Re: Override DPCD information

I'm not sure what you mean. NoDisplayPortBandwidthCheck prevents the driver from considering the DisplayPort bandwidth when validating modes, so it should let through modes that would be valid otherwise and are only rejected because the DP device isn't responding.
AaronP is offline   Reply With Quote
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 03:25 AM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 1998 - 2014, nV News.