Re: [Qemu-devel] [PATCH] Make rtl8139 network interface card compatible with Mac OS 10.4

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

On 30/12/15 16:47, Programmingkid wrote:

> I did disable the change I made to the pci_dma_read() function and applied this
> patch to OpenBIOS. It makes Mac OS X stop booting. This is the message it is
> stuck at when Zoltan's patch is applied:
> mig_table_max_displ = 70
> 
> I even removed the rtl8139 from QEMU's options and Mac OS X still stopped booting
> at the same exact spot. 

Okay. I've just posted a revised patchset to the OpenBIOS list which may
(or may not) help, so please test with that aswell to see if it makes a
difference.

>> It looks like we have to face up to the reality that Apple's OF
>> implementation likes to enable bus mastering for some cards and emulate
>> this behaviour in OpenBIOS, since because of this some drivers don't
>> explicitly enable bus mastering and so fail under emulation.
>>
>> I'll go back and revisit Zoltan's patches to see if we can come up with
>> something that works better for OpenBIOS upstream. In the meantime I
>> still can't quite work out why you still need to swap the BARs around as
>> AFAICT both the mmio and io BARs are mapped onto the chip registers -
>> any chance you could add some debugging to QEMU in order to figure out
>> what is going wrong without your patch?
> 
> I have done a lot of debugging. With only the pci_dma_read() change applied to QEMU, nothing the Mac OS X driver does ever accesses any of the functions from the rtl8139.c file (as far as I can tell). I will add that when this code "if ( csrRead8( RTL_CM ) & R_CM_RST )" is executed by the driver, the value is 16. It appeared to be pretty consistent. The value returned by just "csrRead8( RTL_CM )" is 24. 

Right, so then the question to ask is what is the difference in
behaviours both before and after the BAR swap? It seems that you're
getting a value back but presumably it must be a different value with
your patch applied.


ATB,

Mark.