Bug 20742 – XFree86 MGA driver locks PCI bus

Bug 20742 - XFree86 MGA driver locks PCI bus

Summary:	XFree86 MGA driver locks PCI bus

Status:	CLOSED NOTABUG

Aliases:	None

Product:	Red Hat Linux
Classification:	Retired
Component:	XFree86 (Show other bugs)
Sub Component:
Version:	7.0
Hardware:	i386 Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Mike A. Harris
QA Contact:	David Lawrence
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Reported:	2000-11-12 23:07 EST by Ed McKenzie
Modified:	2007-04-18 12:29 EDT (History)
CC List:	0 users

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Fixed In Version:
Doc Type:	Bug Fix
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Last Closed:	2000-11-19 19:29:38 EST
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Description Ed McKenzie 2000-11-12 23:07:28 EST

Opaque window dragging under XFree86 4 causes sound to get jittery on an MGA g200. This is almost certainly the mga driver locking the PCI bus for imaginary performance gains in bus transfer speed. This wasn't reproducible under 3.3.6.



Changing esd priority to -20 doesn't make things any better.

Comment 1 Alan Cox 2001-01-10 17:44:23 EST

This is a hardware problem with the MGA cards. Matrox lock the PCI bus when the
fifo is full, apparently as a speed hack.

XFree 4.0 has some aggressiveness controls that may help, and the 3.3.x server 
doesnt generally show the problem

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