Panic booting qemu-system-sparc64 with bochs_drm

[Mark Cave-Ayland]

On 04/07/2020 12:11, Mark Cave-Ayland wrote:

> According to gdbstub the destination address in $g3 looks like this:
> 
> Breakpoint 1, 0x00000000007ad8e4 in cfb_imageblit ()
> (gdb) i r $g3
> g3             0x100220000      4297195520
> 
> 
> The 0x100220000 address still isn't right. On sun4u the PCI address space is mapped
> at physical address 0x1fe00000000 and adding these two together gives 0x1ff00220000
> which seems closer, but still not the correct framebuffer address 0x1ff22000000 which
> is reported at boot:
> 
> [    9.007161] [drm] Found bochs VGA, ID 0xb0c5.
> [    9.007840] [drm] Framebuffer size 16384 kB @ 0x1ff22000000, mmio @ 0x1ff23000000.

As a comparison, I took the last known good commit 7a0483ac4ffc~1: "drm/bochs: add
basic prime support" and added some debug in cfb_imageblit() to allow me to pick out
p->screen_base:

(gdb) i r $o1
o1             0x1ff22000000    2195298713600

When running git master with your patch in the same way I get a completely different
value:

(gdb) i r $o1
o1             0x100050000      4295294976

Does p->screen_base need to be initialised differently when using the cfb helpers?


ATB,

Mark.