[OpenBIOS] [Report] Mac OS X Developer Preview

[Mark Cave-Ayland]

On 04/08/16 22:22, BALATON Zoltan wrote:

> On Thu, 4 Aug 2016, Mark Cave-Ayland wrote:
>> This corresponds to this code in QEMU's hw/ide/macio.c:
>>
>>    if (s->lba == -1) {
>>        /* Non-block ATAPI transfer - just copy to RAM */
>>        s->io_buffer_size = MIN(s->io_buffer_size, io->len);
>>        dma_memory_write(&address_space_memory, io->addr, s->io_buffer,
>>                         s->io_buffer_size);
>>        ide_atapi_cmd_ok(s);
>>        m->dma_active = false;
>>        goto done;
>>    }
>>
>> Here the QEMU block code should have already placed the generated TOC
>> into s->io_buffer and DMA the first 14 bytes into RAM but for some
>> reason that's not happening so the code is looping looking for a
>> signature that isn't present.
>>
>> Zoltan: this is very similar to the related issue you had with your
>> MorphOS tests which this code should have resolved, unless I managed to
>> get something wrong in my last rewrite of the macio code?
> 
> The above code did fix this in MorphOS back then but I haven't tried it
> recently (no time for it now). But I'd assume other OS-es would also be
> affected if it broke. Maybe to cross check you could also try OS X DP
> with a version before your last rewrite.

Oh wait - I think the problem is that the status count isn't being set
to zero if you take the non-block codepath, and so the driver may
consider the request failed if it checks res_count afterwards:

pmac_ide_atapi_transfer_cb
DBDMA[1a]: dbdma_end
DBDMA[1a]: conditional_wait
DBDMA[1a]: dbdma_cmdptr_save 0x01072000
DBDMA[1a]: xfer_status 0x00008400 res_count 0x0800
                                            ^^^^^^
DBDMA[1a]: conditional_interrupt
DBDMA[1a]: conditional_branch
DBDMA[1a]: dbdma_cmdptr_load 0x01072010
DBDMA[1a]: channel_run

Does the following patch for QEMU help at all?

diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 5a326af..76f97c2 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -273,6 +273,7 @@ static void pmac_ide_atapi_transfer_cb(void *opaque,
int ret)
         s->io_buffer_size = MIN(s->io_buffer_size, io->len);
         dma_memory_write(&address_space_memory, io->addr, s->io_buffer,
                          s->io_buffer_size);
+        io->len = 0;
         ide_atapi_cmd_ok(s);
         m->dma_active = false;
         goto done;


ATB,

Mark.