From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] USB enclosures seem to require read(16) with >2TB drives Date: Mon, 12 Nov 2012 16:35:25 +0100 Message-ID: <50A1173D.8090603@redhat.com> References: <1352477289-8133-1-git-send-email-hernejj@gmail.com> <1352719990.2449.23.camel@dabdike.int.hansenpartnership.com> <50A10856.6090009@redhat.com> <1352733055.2449.34.camel@dabdike.int.hansenpartnership.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:62999 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752198Ab2KLPfc (ORCPT ); Mon, 12 Nov 2012 10:35:32 -0500 In-Reply-To: <1352733055.2449.34.camel@dabdike.int.hansenpartnership.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: "Jason J. Herne" , linux-scsi , linux-usb@vger.kernel.org, Alan Stern Il 12/11/2012 16:10, James Bottomley ha scritto: >> Actually it only turns it on for large capacity drives, as said in the >> comment. sdp->force_read_16 only matters for >2TB drives: > > If you follow the discussion, we'll need to turn it on for some drives > regardless of size. Even if the two reasons to use r/w(16) commands were setting the same flag, it would be handled in a separate patch; it doesn't really make sense to complicate the code now when a one-liner does it. The proposed change is not part of the Oct 31st draft available on t10.org, for what we know the discussion could end up in nothing. >> > Any reason not to do this always on >2TB drives, which basically means >> > changing this: >> > >> > - } else if (block > 0xffffffff) { >> > + } else if (sdkp->capacity > 0xffffffff) { >> > >> > and nothing else? > Because of the coming T10 mandate in SBC-4 deprecating everything other > than the 16 byte commands. And would this change make the upcoming patch for SBC-4 support longer or harder to review? Paolo