From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthieu CASTET Subject: Re: Buffer I/O error after s2ram with usb storage Date: Mon, 28 Apr 2014 15:01:39 +0200 Message-ID: <20140428150139.0e10dfd9@parrot.com> References: <20140422160115.46d8d2bf@parrot.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20140422160115.46d8d2bf@parrot.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-scsi@vger.kernel.org Cc: James Bottomley , TARUISI Hiroaki , linux-kernel@vger.kernel.org List-Id: linux-scsi@vger.kernel.org Hi, any news on this. Matthieu CASTET Le Tue, 22 Apr 2014 16:01:15 +0200, Matthieu CASTET a =E9crit : > Hi, >=20 > while playing with suspend to ram I found a strange behavior with usb > key. >=20 > This can be easily reproduced by doing : > - plug a usb key > - start to read the usb key : "cat /dev/sdx > /dev/null" > - go to suspend : "echo mem > /sys/power/state" > - while in suspend, unplug and replug the usb key (simulate usb power > loss for computer that keep power) > - exit suspend > - there is read error on the usb key >=20 >=20 > Because the power was cut during s2ram, the usb stack reset the devic= e > <1>. > When new data transfer are done, we got a UNIT_ATTENTION from the > device <2> and IO error are returned to user space application. >=20 > After some investigation it seems some (all on the 3 I tested) usb ke= y > report as removable, and scsi layer abort the transfer in case of > UNIT_ATTENTION <3>. >=20 > The usb storage driver call scsi_report_bus_reset after device reset, > but because of commit dfcf7775 <4>, we don't ignore unit attention if > "sshdr.asc =3D=3D 0x28 && sshdr.ascq =3D=3D 0x00" ("Not-ready to read= y"). >=20 > If dfcf7775 is reverted there is no more Buffer I/O error. >=20 > Is that possible to find a way to restore the behavior before dfcf777= 5 > commit (no Buffer I/O error after device reset) after a suspend to ra= m ? >=20 >=20 > Matthieu CASTET >=20 > PS : the same error happen if sg_reset -b /dev/sdx is used on the > device. >=20 >=20 > <1> > [ 117.070255] usb 2-1.4: reset high-speed USB device number 3 using > ehci-pci [...] > [ 117.543922] Restarting tasks ... done. > [ 117.548390] video LNXVIDEO:01: Restoring backlight state > <2> > [ 117.549179] sd 6:0:0:0: [sdb] Media Changed > [ 117.549184] sd 6:0:0:0: [sdb] =20 > [ 117.549187] Result: hostbyte=3DDID_OK driverbyte=3DDRIVER_SENSE > [ 117.549189] sd 6:0:0:0: [sdb] =20 > [ 117.549191] Sense Key : Unit Attention [current]=20 > [ 117.549195] Info fld=3D0x0 > [ 117.549197] sd 6:0:0:0: [sdb] =20 > [ 117.549201] Add. Sense: Not ready to ready change, medium may have > changed [ 117.549203] sd 6:0:0:0: [sdb] CDB:=20 > [ 117.549205] Read(10): 28 00 00 02 c9 00 00 00 f0 00 > [ 117.549212] end_request: I/O error, dev sdb, sector 182528 > [ 117.549218] Buffer I/O error on device sdb1, logical block 22560 > [ 117.549225] Buffer I/O error on device sdb1, logical block 22561 > [ 117.549228] Buffer I/O error on device sdb1, logical block 22562 > [ 117.549231] Buffer I/O error on device sdb1, logical block 22563 > [ 117.549233] Buffer I/O error on device sdb1, logical block 22564 > [ 117.549235] Buffer I/O error on device sdb1, logical block 22565 > [ 117.549238] Buffer I/O error on device sdb1, logical block 22566 > [ 117.549240] Buffer I/O error on device sdb1, logical block 22567 > [ 117.549243] Buffer I/O error on device sdb1, logical block 22568 > [ 117.549245] Buffer I/O error on device sdb1, logical block 22569 > [ 117.809462] sd 6:0:0:0: [sdb] No Caching mode page found > [ 117.809470] sd 6:0:0:0: [sdb] Assuming drive cache: write through > [ 117.812696] sd 6:0:0:0: [sdb] No Caching mode page found > [ 117.812703] sd 6:0:0:0: [sdb] Assuming drive cache: write through > [ 117.813688] sdb: sdb1 >=20 >=20 > <3> > case UNIT_ATTENTION: > if (cmd->device->removable) { > /* Detected disc change. Set a bit > * and quietly refuse further access. > */ > cmd->device->changed =3D 1; > description =3D "Media Changed"; > action =3D ACTION_FAIL; > } else { > /* Must have been a power glitch, or a > * bus reset. Could not have been a > * media change, so we just retry the > * command and see what happens. > */ > action =3D ACTION_RETRY; > } >=20 > <4> > commit dfcf7775815504d13a1d273073810058caf84b9d > Author: TARUISI Hiroaki > Date: Thu Aug 11 20:25:20 2011 +0900 >=20 > [SCSI] Fix out of spec CD-ROM problem with media change > =20 > Some CD-ROMs fail to report a media change correctly. The specif= ic > one for this patch simply fails to respond to commands, then give= s a > UNIT ATTENTION after being reset which returns ASC/ASCQ 28/00. T= his > is out of spec behaviour, but add a check in the eat CC/UA on res= et > path to catch this case so the CD-ROM will function somewhat prop= erly. > =20 > [jejb: fixed up white space and accepted without signoff] > Signed-off-by: James Bottomley >=20 > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c > index a4b9cdb..dc6131e 100644 > --- a/drivers/scsi/scsi_error.c > +++ b/drivers/scsi/scsi_error.c > @@ -293,8 +293,16 @@ static int scsi_check_sense(struct scsi_cmnd *sc= md) > * so that we can deal with it there. > */ > if (scmd->device->expecting_cc_ua) { > - scmd->device->expecting_cc_ua =3D 0; > - return NEEDS_RETRY; > + /* > + * Because some device does not queue unit > + * attentions correctly, we carefully check > + * additional sense code and qualifier so as > + * not to squash media change unit attention. > + */ > + if (sshdr.asc !=3D 0x28 || sshdr.ascq !=3D 0x= 00) { > + scmd->device->expecting_cc_ua =3D 0; > + return NEEDS_RETRY; > + } > } > /* > * if the device is in the process of becoming ready,= we