Re: [Qemu-devel] [PATCH] Cirrus bugfixes

[Volker Ruppert]

Hi,

> I was wondering - is this patch affects only the ISA part of the
> Cirrus emulation?

No, this patch also affects the PCI version of the Cirrus adapter. I did my 
tests mostly with the ISA version to find out the bugs. The Win 3.11 driver 
for the CL-GD5430 seems to use more of the currently unimplemented features 
than the PCI driver for Win95 does.

> Also, forgive me for asking, but why do you use the ISA
> implementation? I'm sure there are drivers for both win 3.11 and
> win95/98 for the PCI Cirrus..

I know that there are drivers for PCI and I'm using the Qemu PCI system for 
Win95/98, but using Win3.11 on ISA was the best way to find out how the 
bitblt destination write mask should work.
Here is the list of changes with some additions:

 - partial implementation of the destination write mask (bit 7 unhandled)

   This affects ISA and PCI on Win3.1x,Win9x and maybe others. It fixes the
   Win95 tooltips and the Borders of selected items on Win3.11 with Calmira
   II. This is the most important part of the patch.

 - fixed banked memory access of the ISA version

   This description is wrong. Banked memory access is possible on PCI, too,
   but the PCI drivers usually using the LFB.

 - the bus type bits in sequencer reg 0x17 must be readonly

   Without this change the bus type bits can be changed by software. This
   shouldn't happen. The Cirrus driver for Win3.11 probes this register and
   tries to overwrite these bits (switches from ISA to PCI).

 - fixed destination write mask in debug message

   This bugfix made it possible to find the other bugs. First I was wondering
   why the value was always 0, but I expected something else.

--
Bye

Volker