Package: linux-2.6
Tags: patch upstream
Blocks: 581791

This should fix #581791.

----- Forwarded message from Tejun Heo <t...@kernel.org> -----

From: Tejun Heo <t...@kernel.org>
To: Jeff Garzik <j...@garzik.org>,
        "linux-...@vger.kernel.org" <linux-...@vger.kernel.org>
CC: Kay Sievers <kay.siev...@vrfy.org>,
        Nick Bowler <nbow...@elliptictech.com>,
        David Zeuthen <da...@fubar.dk>, linux-hotp...@vger.kernel.org,
        sta...@kernel.org
Subject: [PATCH #upstream-fixes] libata: disable ATAPI AN by default

There are ATAPI devices which raise AN when hit by commands issued by
open().  This leads to infinite loop of AN -> MEDIA_CHANGE uevent ->
udev open() to check media -> AN.

Both ACS and SerialATA standards don't define in which case ATAPI
devices are supposed to raise or not raise AN.  They both list media
insertion event as a possible use case for ATAPI ANs but there is no
clear description of what constitutes such events.  As such, it seems
a bit too naive to export ANs directly to userland as MEDIA_CHANGE
events without further verification (which should behave similarly to
windows as it apparently is the only thing that some hardware vendors
are testing against).

This patch adds libata.atapi_an module parameter and disables ATAPI AN
by default for now.

Signed-off-by: Tejun Heo <t...@kernel.org>
Cc: Kay Sievers <kay.siev...@vrfy.org>
Cc: Nick Bowler <nbow...@elliptictech.com>
Cc: David Zeuthen <da...@fubar.dk>
Cc: sta...@kernel.org
---
 drivers/ata/libata-core.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 49cffb6..5abab5d 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -160,6 +160,10 @@ int libata_allow_tpm = 0;
 module_param_named(allow_tpm, libata_allow_tpm, int, 0444);
 MODULE_PARM_DESC(allow_tpm, "Permit the use of TPM commands (0=off [default], 
1=on)");

+static int atapi_an;
+module_param(atapi_an, int, 0444);
+MODULE_PARM_DESC(atapi_an, "Enable ATAPI AN media presence notification (0=0ff 
[default], 1=on)");
+
 MODULE_AUTHOR("Jeff Garzik");
 MODULE_DESCRIPTION("Library module for ATA devices");
 MODULE_LICENSE("GPL");
@@ -2572,7 +2576,8 @@ int ata_dev_configure(struct ata_device *dev)
                 * to enable ATAPI AN to discern between PHY status
                 * changed notifications and ATAPI ANs.
                 */
-               if ((ap->flags & ATA_FLAG_AN) && ata_id_has_atapi_AN(id) &&
+               if (atapi_an &&
+                   (ap->flags & ATA_FLAG_AN) && ata_id_has_atapi_AN(id) &&
                    (!sata_pmp_attached(ap) ||
                     sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf) == 0)) {
                        unsigned int err_mask;
--
To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

----- End forwarded message -----

-- 
ciao,
Marco

Attachment: signature.asc
Description: Digital signature

Reply via email to