From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pat LaVarre Subject: Re: [linux-usb-devel] [2.6-test] Bug in usb-storage or scsi? Date: 10 Sep 2003 15:07:08 -0600 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1063228028.6151.1.camel@patehci2> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from email-out1.iomega.com ([147.178.1.82]:24209 "EHLO email.iomega.com") by vger.kernel.org with ESMTP id S265726AbTIJV1b (ORCPT ); Wed, 10 Sep 2003 17:27:31 -0400 List-Id: linux-scsi@vger.kernel.org To: stern@rowland.harvard.edu Cc: mdharm-usb@one-eyed-alien.net, usb-storage@one-eyed-alien.net, linux-scsi@vger.kernel.org I see Google didn't thread my first try properly, sorry. Here I am again with an edited subject line. -----Forwarded Message----- From: Pat LaVarre To: stern@rowland.harvard.edu Cc: mdharm-usb@one-eyed-alien.net, usb-storage@one-eyed-alien.net, linux-scsi@vger.kernel.org Subject: Re: [usb-storage] Re: [linux-usb-devel] [2.6-test] Bug in usb-storage or scsi? Date: 10 Sep 2003 12:16:31 -0600 > What do the SCSI folk have to say about it? Anyone? > > for 2.6.0 ... drivers/scsi/sd.c ... > > sd_read_cache_type ... > > Get rid of (or #ifdef out) most ... > > Is there any feeling about how to handle these > ongoing problems with the mode-sense cache > page? Yes, much. Maybe more feeling if you remind/teach me what breaks if we don't fetch page 8 re Cache. First I imagine automounters mount read-only disks rw, and then the write cache gets errors while flushing. I wonder what else breaks. Maybe thruput varies for devices that do or do not bother to claim they have write cache. Maybe more feeling if you can say how in/accurate page 8 re Cache commonly is. For example, I know of no clear & broadly adopted standard that requires a device to declare write-behind or background defect map updates as a form of write cache. > There doesn't seem to be any general solution > that can work with all USB storage devices. I understand you to be saying we can settle for an sd solution, we don't mind if the sd heuristic we discover then doesn't apply to pdt x05 dvd/cd. > some hang when asked to read just the page > header. > ... > some hang when asked to read just part of the > page; > ... > Some hang when asked to read the entire page; Device folk ship bugs, aye, same as host folk. Are not two of these three failures disproportionately common? Me, I would expect asking anything but what Windows asks would fail most often. Is that not so? Do we know what Windows asks? Do we know if/how Win ME/ 2K/ XP differ here? Have we matched CBWCB and dCBWDataTransferLength in every bit? Pat LaVarre