linux-kernel - [PATCH] 2.6.26-mmotm tpm-correct-tpm-timeouts-to-jiffies-conversion-d820-fix.patch

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Date:	Sat, 26 Jul 2008 00:03:53 -0400
From:	Valdis.Kletnieks@...edu
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Marcin Obara <marcin_obara@...rs.sourceforge.net>
Cc:	linux-kernel@...r.kernel.org, Marcel Selhorst <tpm@...horst.net>,
	Kylene Jo Hall <kjhall@...ibm.com>,
	tpmdd-devel@...ts.sourceforge.net
Subject: [PATCH] 2.6.26-mmotm tpm-correct-tpm-timeouts-to-jiffies-conversion-d820-fix.patch

Patch tpm-correct-tpm-timeouts-to-jiffies-conversion reveals a bug in the
Broadcom BCM0102 TPM chipset used in the Dell Latitude D820 - although most of
the timeouts are returned in usecs as per the spec, one is apparently returned
in msecs, which results in a timeout when the code treats it as usecs.  To
prevent a regression, we check for the known too-short value and adjust it to a
value that makes things work.

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@...edu>
cc: Marcin Obara <marcin_obara@...rs.sourceforge.net>

--- linux-2.6.26-mmotm-0724/drivers/char/tpm/tpm.c.broadcom	2008-07-25 22:13:47.000000000 -0400
+++ linux-2.6.26-mmotm-0724/drivers/char/tpm/tpm.c	2008-07-25 23:30:38.000000000 -0400
@@ -557,6 +557,13 @@ duration:
 	    usecs_to_jiffies(be32_to_cpu
 			     (*((__be32 *) (data +
 					    TPM_GET_CAP_RET_UINT32_1_IDX))));
+	/* The Broadcom BCM0102 chipset in a Dell Latitude D820 gets the above
+	 * value wrong and apparently reports msecs rather than usecs. Test
+	 * for the specific buggy value and adjust it to prevent a regression.
+	 */
+	if (chip->vendor.duration[TPM_SHORT] == 1)
+		chip->vendor.duration[TPM_SHORT] *= 1000;
+
 	chip->vendor.duration[TPM_MEDIUM] =
 	    usecs_to_jiffies(be32_to_cpu
 			     (*((__be32 *) (data +


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