Re: [Qemu-devel] [PATCHv2] macio: handle non-block ATAPI DMA transfers the same as block DMA transfers

[Aurelien Jarno <aurelien@aurel32.net>]

On 2015-08-01 17:54, Mark Cave-Ayland wrote:
> The existing code incorrectly changes the dma_active flag when a non-block
> transfer has completed leading to a hang on newer versions of Linux because the
> IDE and DMA engines deadlock waiting for each other.
> 
> Instead copy the buffer directly to RAM, set the remaining transfer size to 0 and
> then invoke the ATAPI callback manually once again to correctly finish the
> transfer in an identical manner to a block transfer.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---

Thanks for the patch, it improves things here. I don't get messages
anymore, and I get less messages when mounting the CD-ROM, though I
still get one:

  [  307.258463] pata-macio 0.00021000:ata-4: timeout flushing DMA
  [  307.262856] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
  [  307.262919] ata2.00: BMDMA stat 0x6
  [  307.263048] sr 1:0:0:0: CDB: Get configuration: 46 00 00 28 00 00 00 00 10 00
  [  307.263289] ata2.00: cmd a0/01:00:00:10:00/00:00:00:00:00/a0 tag 0 dma 16400 in
  [  307.263297]          res 41/50:03:00:10:00/00:00:00:00:00/a0 Emask 0x20 (host bus error)
  [  307.263407] ata2.00: status: { DRDY ERR }
  [  307.271251] ata2.00: configured for MWDMA2
  [  307.271824] ata2: EH complete

The CD-ROM is fully functional though.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net