malc schrieb: > On Sun, 15 Nov 2009, Stefan Weil wrote: > > >> malc schrieb: >> >>> On Sun, 15 Nov 2009, Gleb Natapov wrote: >>> > > [..snip..] > > >> Here is a summary of my analysis of this problem: >> >> Graphics mode memory (ram 0xe0000000 ...) is not mapped >> in QEMU address space (which results in unassigned >> memory writes) for standard pci vga (-vga std), so users >> don't get vga display output with grub (in graphical mode), >> debian installer (in graphical mode) or similar boot software. >> >> This happens for PC system emulation using SeaBIOS. >> It won't happen when using Bochs BIOS. >> >> Other system emulations which can run standard pci vga >> seem to suffer from the same problem: when I run mips >> malta using -vga std, it won't display anything on the vga >> screen (it works with cirrus pci vga). >> >> Malta has no vga bios, so the error might be in QEMU's >> vga code (hw/vga-pci.c). Maybe wrong initial PCI mappings? >> Maybe this has always be wrong (which would explain why >> git bisect does not work). >> > > git bisect doesn't work because most of the time: > > a. Compilation fails > b. Compilation succeeds but qemu segfaults before even trying to > execute any guest code >
I did git bisect: even very early versions (from 2006) of std vga had the same kind of problem (no access to frame buffer at 0xe0000000) when booted with SeaBIOS). It was not really a bisection, because I never reached status "good".
