From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: READ_CAPACITY_16 vs. READ_CAPACITY_10 Date: Thu, 12 Sep 2013 07:56:02 +0200 Message-ID: <52315772.8040402@suse.de> References: <1378821408.13541.26.camel@linux-fkkt.site> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:45169 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753315Ab3ILF4D (ORCPT ); Thu, 12 Sep 2013 01:56:03 -0400 In-Reply-To: <1378821408.13541.26.camel@linux-fkkt.site> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Oliver Neukum Cc: Alan Stern , linux-scsi@vger.kernel.org On 09/10/2013 03:56 PM, Oliver Neukum wrote: > Hi Hannes, >=20 > you objected to this patch saying there's a possibilty that > HS devices may also need this feature, which would require > a quirk. Does this mean that the patch is acceptable only > with an additional predefined quirk, or do you insist that all > devices be handled with quirks? >=20 > Regards > Oliver >=20 > +++ b/drivers/usb/storage/scsiglue.c > @@ -211,8 +211,11 @@ static int slave_configure(struct > scsi_device0*sdev) > /* > * Many devices do not respond properly to READ_CAPACITY_16. > * Tell the SCSI layer to try READ_CAPACITY_10 first. > + * However some USB 3.0 drive enclosures return capacity > + * modulo 2TB > */ > - sdev->try_rc_10_first =3D 1; > + if (us->pusb_dev->speed < USB_SPEED_SUPER) > + sdev->try_rc_10_first =3D 1; > =20 > /* assume SPC3 or latter devices support sense size > 18 */ > if (sdev->scsi_level > SCSI_SPC_2) >=20 Predefined quirks is okay. My main objection here is that the original issue most likely is a buggy firmware, so there is a _very_ good chance that it'll be resolved in firmware in the near future. At the same time, other firmwares might continue to not support READ_CAPACITY_16 while enabling HS. So both issues really should be kept separate, which'll warrant a new flag. Which of course could be set to on per default on HS devices. As long as we can switch is off again ... Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg GF: J. Hawn, J. Guild, F. Imend=C3=B6rffer, HRB 16746 (AG N=C3=BCrnberg= ) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html