From: Matthew Wilcox <matthew@wil.cx>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hans de Goede <hdegoede@redhat.com>,
Ben Hutchings <ben@decadent.org.uk>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"alan@lxorguk.ukuu.org.uk" <alan@lxorguk.ukuu.org.uk>,
Matthew Dharm <mdharm-usb@one-eyed-alien.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [ 38/48] SCSI & usb-storage: add try_rc_10_first flag
Date: Tue, 3 Jul 2012 11:32:31 -0600 [thread overview]
Message-ID: <20120703173231.GC28804@parisc-linux.org> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1207031142210.17487-100000@netrider.rowland.org>
On Tue, Jul 03, 2012 at 11:49:00AM -0400, Alan Stern wrote:
> On Tue, 3 Jul 2012, James Bottomley wrote:
>
> > > What happened is that T10
> > > in their infinite wisdom decided to put things like "supports TRIM" and
> > > "is actually a 4k block size but fakes 512 byte blocks" in the Read
> > > Capacity 16 results. So if we want to support those kinds of things
> > > (and I think we do), then we need to send Read Capacity 16 to devices.
> >
> > But anyway, we're stuck ... we have to send RC16 first to support these
> > features. We did protest to T10 at the time, but to no avail.
>
> Does it have to be sent _first_?
>
> Or would it be okay to send _both_ commands and believe the RC10
> capacity rather than the RC16 capacity if they differ?
I have no problem with doing that (and believing RC16 over RC10 if RC10
claims 0xffffffff, naturally). The problem, as I understand it, is that
some devices crash upon receiving RC16 rather than just returning nonsense.
> > I still think a whitelist of USB devices sending proper SCSI level
> > information in the inquiry might be the best way forward.
>
> I'm doubtful. It wouldn't be at all surprising for devices to claim
> they support a particular level when in fact they support some but not
> all of the required commands. Then what do you do? Put them on the
> whitelist because of the commands they support, or leave them off
> because of the other ones? What happens later on when you decide to
> use more of the required commands?
SCSI has a fairly extensive collection of black/white list flags already
... see scsi_devinfo.[ch].
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2012-07-03 17:32 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120701172006.535271340@decadent.org.uk>
2012-07-01 17:20 ` [ 01/48] staging:iio:ad7606: Re-add missing scale attribute Ben Hutchings
2012-07-01 17:20 ` [ 02/48] Tools: hv: verify origin of netlink connector message Ben Hutchings
2012-07-01 17:20 ` [ 03/48] edac: avoid mce decoding crash after edac driver unloaded Ben Hutchings
2012-07-01 17:20 ` [ 06/48] hwmon: (applesmc) Limit key length in warning messages Ben Hutchings
2012-07-01 17:20 ` [ 07/48] mm: fix slab->page _count corruption when using slub Ben Hutchings
2012-07-02 23:46 ` Herton Ronaldo Krzesinski
2012-07-02 23:56 ` Herton Ronaldo Krzesinski
2012-07-03 1:17 ` Herton Ronaldo Krzesinski
2012-07-03 20:19 ` Pravin Shelar
2012-07-04 4:36 ` Ben Hutchings
2012-07-01 17:20 ` [ 08/48] mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition Ben Hutchings
2012-07-01 17:20 ` [ 10/48] nilfs2: ensure proper cache clearing for gc-inodes Ben Hutchings
2012-07-01 17:20 ` [ 12/48] drm/i915: Finish any pending operations on the framebuffer before disabling Ben Hutchings
2012-07-01 17:20 ` [ 13/48] drm/i915: Remove use of the autoreported ringbuffer HEAD position Ben Hutchings
2012-07-01 17:20 ` [ 15/48] e1000e: Remove special case for 82573/82574 ASPM L1 disablement Ben Hutchings
2012-07-01 22:59 ` Jonathan Nieder
2012-07-01 17:20 ` [ 16/48] drm/i915: Do the fallback non-IRQ wait in ring throttle, too Ben Hutchings
2012-07-01 17:20 ` [ 17/48] staging:rts_pstor:Fix possible panic by NULL pointer dereference Ben Hutchings
2012-07-01 17:20 ` [ 21/48] drm/nouveau/fbcon: using nv_two_heads is not a good idea Ben Hutchings
2012-07-01 17:20 ` [ 29/48] ARM: SAMSUNG: Should check for IS_ERR(clk) instead of NULL Ben Hutchings
2012-07-01 17:20 ` [ 30/48] ath9k_hw: avoid possible infinite loop in ar9003_get_pll_sqsum_dvc Ben Hutchings
2012-07-01 17:20 ` [ 31/48] iwlwifi: remove log_event debugfs file debugging is disabled Ben Hutchings
2012-07-01 17:20 ` [ 32/48] ARM: SAMSUNG: Fix for S3C2412 EBI memory mapping Ben Hutchings
2012-07-01 17:20 ` [ 33/48] USB: option: add id for Cellient MEN-200 Ben Hutchings
2012-07-01 17:20 ` [ 34/48] oprofile: perf: use NR_CPUS instead or nr_cpumask_bits for static array Ben Hutchings
2012-07-01 17:20 ` [ 35/48] drm/i915: Refactor the deferred PM_IIR handling into a single function Ben Hutchings
2012-07-01 17:20 ` [ 36/48] drm/i915: rip out the PM_IIR WARN Ben Hutchings
2012-07-01 17:20 ` [ 37/48] drm/i915: Fix eDP blank screen after S3 resume on HP desktops Ben Hutchings
2012-07-01 17:20 ` [ 38/48] SCSI & usb-storage: add try_rc_10_first flag Ben Hutchings
2012-07-02 7:10 ` Hans de Goede
2012-07-02 18:52 ` Linus Torvalds
2012-07-02 20:39 ` James Bottomley
2012-07-02 22:23 ` Linus Torvalds
2012-07-03 0:41 ` Matthew Wilcox
2012-07-03 6:18 ` James Bottomley
2012-07-03 15:49 ` Alan Stern
2012-07-03 17:32 ` Matthew Wilcox [this message]
2012-07-03 19:50 ` Alan Stern
2012-07-03 20:07 ` James Bottomley
2012-07-03 20:25 ` Alan Stern
2012-07-03 20:35 ` Matthew Wilcox
2012-07-05 21:40 ` Alan Stern
2012-07-06 3:05 ` Matthew Wilcox
2012-07-06 14:00 ` Alan Stern
2012-07-04 4:39 ` Ben Hutchings
2012-07-01 17:20 ` [ 39/48] PM / Sleep: Prevent waiting forever on asynchronous suspend after abort Ben Hutchings
2012-07-01 17:20 ` [ 40/48] x86, cpufeature: Rename X86_FEATURE_DTS to X86_FEATURE_DTHERM Ben Hutchings
2012-07-01 17:20 ` [ 42/48] ALSA: hda - Add Realtek ALC280 codec support Ben Hutchings
2012-07-01 17:20 ` [ 43/48] USB: option: Add USB ID for Novatel Ovation MC551 Ben Hutchings
2012-07-01 17:20 ` [ 45/48] xen/netfront: teardown the device before unregistering it Ben Hutchings
2012-07-01 17:20 ` [ 46/48] can: flexcan: use be32_to_cpup to handle the value of dt entry Ben Hutchings
2012-07-01 17:20 ` [ 47/48] acpi_pad: fix power_saving thread deadlock Ben Hutchings
2012-07-01 17:20 ` [ 48/48] batman-adv: only drop packets of known wifi clients Ben Hutchings
2012-07-01 19:11 ` [ 00/48] 3.2.22-stable review Ben Hutchings
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