Re: [Qemu-devel] SeaBIOS regression

[Thomas Huth]

On 2019-02-05 10:42, Gerd Hoffmann wrote:
> On Tue, Feb 05, 2019 at 10:31:24AM +0100, Thomas Huth wrote:
>> On 2019-02-05 08:52, Gerd Hoffmann wrote:
>>> On Mon, Feb 04, 2019 at 04:10:37PM +0100, Thomas Huth wrote:
>>>>
>>>>  Hi Gerd,
>>>>
>>>> I noticed that certain FreeDOS images are not working correctly anymore
>>>> with the current version of QEMU, for example
>>>> http://www.qemu-advent-calendar.org/2016/download/day10.tar.xz ... It
>>>> aborts with:
>>>>
>>>>  Error reading from drive C: DOS area: write-protection violation attempted
>>>>
>>>> I've bisected the issue, and it has apparently been introduced with:
>>>>
>>>>  cd1bfd5ef336166b275a09dc9842542bf5e63ae3
>>>>  seabios: update bios and vgabios binaries
>>>>
>>>> Any idea what might be going wrong here?
>>>
>>> Hmm, no.  bisect seabios?
>>
>> I haven't bisected yet, but it seems to be related to CONFIG_ATA_DMA=y
>> in our roms/config.seabios-128k config file. When I switch that to "n",
>> then the old FreeDOS disks are working again...
> 
> Hmm, guess I should turn that off again on the next update (there will
> be a seabios 1.12.1 release before qemu 4.0).

Ah, right, I just noticed that this has just been enabled in QEMU for
the 3.0 release, where the problem occurred for the first time. So this
switch is likely the culprit, not a change in SeaBIOS. I'd also vote to
revert commit eda553a442e94d now.

 Thomas