Changes between Initial Version and Version 1 of Ticket #5383


Ignore:
Timestamp:
Feb 8, 2010, 3:53:43 PM (12 years ago)
Author:
rudolfc
Comment:

Legend:

Unmodified
Added
Removed
Modified
  • Ticket #5383 – Description

    initial v1  
    11Since r34197 MTRR doesn't work OK anymore on my ASUS P4 mainboard with AGP slot.
    22
    3 The nvidia kerneldriver maps a 1Mb buffer using MTRR in main system memory. This buffer is written to by the CPU, and it's read by the GPU using AGP transfers.
     3The nvidia kerneldriver maps a 1Mb buffer using MTRR-WC in main system memory. This buffer is written to by the CPU, and it's read by the GPU using AGP transfers.
    44It turns out that the GPU sees an inconsistently written buffer which results in old / partially degraded commands being executed by the engine, resulting in an engine hang in the end.
    5 Using PCI transfers this problem doesn't occur. If I relocate the buffer to gfx memory, this problem doesn't occur. If I disable MTRR mapping in the kerneldriver the problem remains in AGP.
     5Using PCI transfers this problem doesn't occur. If I relocate the buffer to gfx memory, this problem doesn't occur. If I disable MTRR-WC mapping in the kerneldriver the problem remains in AGP.
    66
    77On PCIe systems this problem doesn't exist.