All of lore.kernel.org
 help / color / mirror / Atom feed
From: Paolo Bonzini <pbonzini@redhat.com>
To: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>,
	qemu-devel@nongnu.org, fam@euphon.net, laurent@vivier.eu,
	hpoussin@reactos.org
Subject: Re: [PATCH 4/5] esp: revert 75ef849696 "esp: correctly fill bus id with requested lun"
Date: Wed, 9 Jun 2021 14:13:09 +0200	[thread overview]
Message-ID: <09e11569-b61e-db90-efe8-7f2f3c3d4cad@redhat.com> (raw)
In-Reply-To: <20210519100803.10293-5-mark.cave-ayland@ilande.co.uk>

On 19/05/21 12:08, Mark Cave-Ayland wrote:
> This commit from nearly 10 years ago no longer appears to be required and in its
> current form prevents the MacOS CDROM driver from detecting the CDROM drive. The
> error is caused by the MacOS CDROM driver sending this CDB without DMA:
> 
>      0x12 0x00 0x00 0x00 0x05 0x00 (INQUIRY)
> 
> This is a valid INQUIRY command, however with this logic present the 3rd byte
> (0x0) is copied over the 1st byte (0x12) which silently converts the INQUIRY
> command to a TEST UNIT READY command before passing it to the QEMU SCSI layer.
> Since the TEST UNIT READY command has a zero length response the MacOS CDROM
> driver never receives a response and assumes the CDROM is not present.
> 
> Resolve the issue by reverting the original commit which I'm fairly sure is now
> obsolete so that the original MacOS CDB is passed unaltered to the QEMU SCSI
> layer.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>   hw/scsi/esp.c | 3 ---
>   1 file changed, 3 deletions(-)
> 
> diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
> index afb4a7f9f1..a6f7c6c1bf 100644
> --- a/hw/scsi/esp.c
> +++ b/hw/scsi/esp.c
> @@ -260,9 +260,6 @@ static uint32_t get_cmd(ESPState *s, uint32_t maxlen)
>               return 0;
>           }
>           n = esp_fifo_pop_buf(&s->fifo, buf, dmalen);
> -        if (n >= 3) {
> -            buf[0] = buf[2] >> 5;
> -        }
>           n = MIN(fifo8_num_free(&s->cmdfifo), n);
>           fifo8_push_all(&s->cmdfifo, buf, n);
>       }
> 

This is probably related to S vs SATN, and the bug is that it's doing it 
even in the S case where cmdfifo_cdb_offset is zero.  You can see that 
the flow is

bus[0] = bus[2] >> 5;
    -> busid = esp_fifo_pop(&s->cmdfifo);    [do_cmd]
         -> lun = busid & 7;                 [do_busid_cmd]

However it does seem bogus.

Perhaps the "S without ATN" cases (handle_s_without_atn, 
s_without_satn_pdma_cb) should do something like

    busid = (busid & ~7) | (buf[2] >> 5);

before calling do_busid_cmd?

Paolo



  reply	other threads:[~2021-06-09 12:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-19 10:07 [PATCH 0/5] esp: fixes for MacOS toolbox ROM Mark Cave-Ayland
2021-05-19 10:07 ` [PATCH 1/5] esp: allow non-DMA callback in esp_transfer_data() initial transfer Mark Cave-Ayland
2021-05-19 10:08 ` [PATCH 2/5] esp: handle non-DMA transfers from the target one byte at a time Mark Cave-Ayland
2021-05-19 10:08 ` [PATCH 3/5] esp: ensure PDMA write transfers are flushed from the FIFO to the target immediately Mark Cave-Ayland
2021-05-19 10:08 ` [PATCH 4/5] esp: revert 75ef849696 "esp: correctly fill bus id with requested lun" Mark Cave-Ayland
2021-06-09 12:13   ` Paolo Bonzini [this message]
2021-06-09 15:31     ` Mark Cave-Ayland
2021-06-11 11:38       ` Paolo Bonzini
2021-06-11 11:52         ` Mark Cave-Ayland
2021-05-19 10:08 ` [PATCH 5/5] esp: correctly accumulate extended messages for PDMA Mark Cave-Ayland
2021-05-28  7:11 ` [PATCH 0/5] esp: fixes for MacOS toolbox ROM Mark Cave-Ayland
2021-06-07 11:00   ` Mark Cave-Ayland
2021-06-09 12:13 ` Paolo Bonzini

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=09e11569-b61e-db90-efe8-7f2f3c3d4cad@redhat.com \
    --to=pbonzini@redhat.com \
    --cc=fam@euphon.net \
    --cc=hpoussin@reactos.org \
    --cc=laurent@vivier.eu \
    --cc=mark.cave-ayland@ilande.co.uk \
    --cc=qemu-devel@nongnu.org \
    --subject='Re: [PATCH 4/5] esp: revert 75ef849696 "esp: correctly fill bus id with requested lun"' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.