Bug 92311 - vga corruption on SM 750 GPU
Summary: vga corruption on SM 750 GPU
Status: NEEDINFO
Alias: None
Product: Drivers
Classification: Unclassified
Component: Video(Other) (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: drivers_video-other
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-01-29 23:41 UTC by Dave Airlie
Modified: 2015-02-10 15:37 UTC (History)
1 user (show)

See Also:
Kernel Version: 3.19
Subsystem:
Regression: No
Bisected commit-id:

Attachments
image showing corruption (49.88 KB, image/png)
2015-01-29 23:41 UTC, Dave Airlie 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Dave Airlie 2015-01-29 23:41:54 UTC 
Created attachment 165221 [details]
image showing corruption

Due to a hw bug in ths GPU 64-bit writes to the VGA seem to corrupt things.

Originally reported in RH bugzilla against RHEL6 vs RHEL5 behaviour on 32 vs 64-bit systems.

Steps to Reproduce:
1.modify the runlevel to 3, to use vga mode.
2.use vim to edit some file, and scroll up
3.the vga display messy code
Comment 1 Alan 2015-02-10 15:37:26 UTC 
Is it the 64bit wide writes or reads that do the damage.

Is the framebuffer memory marked write combining at the bridge ?
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