From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
To: Mikael Pettersson <mikpe@it.uu.se>
Cc: linux-ide@vger.kernel.org
Subject: Re: 2.6.24-rc1 IDE regression on PMAC?
Date: Sat, 27 Oct 2007 21:19:42 +0200 [thread overview]
Message-ID: <200710272119.42791.bzolnier@gmail.com> (raw)
In-Reply-To: <200710271756.l9RHuKub021729@harpo.it.uu.se>
On Saturday 27 October 2007, Mikael Pettersson wrote:
> As shown by this dmesg diff between 2.6.23 and 2.6.24-rc1,
> IDE's PMAC driver now decides to downgrade itself to PIO2
> on this box. Is this intensional or a bug?
This drive still uses MWDMA1 according to the dmesg diff
(only the debug message from IDE PMAC is gone) but since we
have enabled PIO autotuning PIO is also tuned.
PIO downgrade is kind of expected for drives that doesn't
support PIO4 (this drive's max is PIO3).
The guilty code is in ide_get_best_pio_mode():
/*
* Conservative "downgrade" for all pre-ATA2 drives
*/
if ((drive->hwif->host_flags & IDE_HFLAG_PIO_NO_DOWNGRADE) == 0 &&
pio_mode && pio_mode < 4) {
pio_mode--;
printk(KERN_INFO "%s: applying conservative "
"PIO \"downgrade\"\n", drive->name);
}
and is/was? probably needed only for CMD640 host driver so you
may try adding IDE_HFLAG_PIO_NO_DOWNGRADE to IDE PMAC driver
and see what happens. :)
> --- dmesg-2.6.23
> +++ dmesg-2.6.24-rc1
> @@ -84,8 +89,9 @@
> ide0: Found Apple Heathrow ATA controller, bus ID 0, irq 28
> Probing IDE interface ide0...
> hda: MATSHITA CR-585, ATAPI CD/DVD-ROM drive
> +hda: applying conservative PIO "downgrade"
> +hda: host max PIO4 wanted PIO255(auto-tune) selected PIO2
> hda: selected mode 0x21
0x21 == MWDMA1
Yeah, needs fixing to call ide_xfer_verbose() which prints something
human-readable. I'll look into this, unless somebody beats me to it.
> -hda: Enabling MultiWord DMA 1
> ide0 at 0xf1008000-0xf1008007,0xf1008160 on irq 28
> ide1: Found Apple Heathrow ATA controller, bus ID 1, irq 30
> Probing IDE interface ide1...
Thanks,
Bart
prev parent reply other threads:[~2007-10-27 19:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-27 17:56 2.6.24-rc1 IDE regression on PMAC? Mikael Pettersson
2007-10-27 19:19 ` Bartlomiej Zolnierkiewicz [this message]
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=200710272119.42791.bzolnier@gmail.com \
--to=bzolnier@gmail.com \
--cc=linux-ide@vger.kernel.org \
--cc=mikpe@it.uu.se \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).