Date: Mon, 8 May 2017 18:30:55 +0000 (UTC) From: "Kenneth D. Merry" <ken@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r317965 - stable/11/sbin/camcontrol Message-ID: <201705081830.v48IUt6Y073960@repo.freebsd.org>
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Author: ken Date: Mon May 8 18:30:55 2017 New Revision: 317965 URL: https://svnweb.freebsd.org/changeset/base/317965 Log: MFC r317854: When editing a mode page on a tape drive, do not clear the device specific parameter. Tape drives include write protect (WP), Buffered Mode and Speed settings in the device-specific parameter. Clearing this parameter on a mode select can have the effect of turning off write protect or buffered mode, or changing the speed setting of the tape drive. Disks report DPO/FUA support via the device specific parameter for MODE SENSE, but the bit is reserved for MODE SELECT. So we clear this for disks (and other non-tape devices) to avoid potential errors from the target device. sbin/camcontrol/modeedit.c: Clear the device-specific parameter in the mode page header if we're not operating on a tape drive. Sponsored by: Spectra Logic Modified: stable/11/sbin/camcontrol/modeedit.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sbin/camcontrol/modeedit.c ============================================================================== --- stable/11/sbin/camcontrol/modeedit.c Mon May 8 17:55:51 2017 (r317964) +++ stable/11/sbin/camcontrol/modeedit.c Mon May 8 18:30:55 2017 (r317965) @@ -629,8 +629,21 @@ editlist_save(struct cam_device *device, /* Recalculate headers & offsets. */ mh->data_length = 0; /* Reserved for MODE SELECT command. */ - mh->dev_spec = 0; /* Clear device-specific parameters. */ mh->blk_desc_len = 0; /* No block descriptors. */ + /* + * Tape drives include write protect (WP), Buffered Mode and Speed + * settings in the device-specific parameter. Clearing this + * parameter on a mode select can have the effect of turning off + * write protect or buffered mode, or changing the speed setting of + * the tape drive. + * + * Disks report DPO/FUA support via the device specific parameter + * for MODE SENSE, but the bit is reserved for MODE SELECT. So we + * clear this for disks (and other non-tape devices) to avoid + * potential errors from the target device. + */ + if (device->pd_type != T_SEQUENTIAL) + mh->dev_spec = 0; mph = MODE_PAGE_HEADER(mh); mph->page_code &= ~SMPH_PS; /* Reserved for MODE SELECT command. */
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