Bug 20742 - XFree86 MGA driver locks PCI bus
XFree86 MGA driver locks PCI bus
Product: Red Hat Linux
Classification: Retired
Component: XFree86 (Show other bugs)
i386 Linux
medium Severity medium
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Assigned To: Mike A. Harris
David Lawrence
Depends On:
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Reported: 2000-11-12 23:07 EST by Ed McKenzie
Modified: 2007-04-18 12:29 EDT (History)
0 users

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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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