Changes between Initial Version and Version 1 of Ticket #5383
- Timestamp:
- Feb 8, 2010, 3:53:43 PM (15 years ago)
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Ticket #5383 – Description
initial v1 1 1 Since r34197 MTRR doesn't work OK anymore on my ASUS P4 mainboard with AGP slot. 2 2 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.3 The 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. 4 4 It 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.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-WC mapping in the kerneldriver the problem remains in AGP. 6 6 7 7 On PCIe systems this problem doesn't exist.
