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Commit 292cf4a8 authored by Valdis Kletnieks's avatar Valdis Kletnieks Committed by Linus Torvalds
Browse files

tpm: work around bug in Broadcom BCM0102 chipset 



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 too-small value leading
to 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: default avatarValdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Marcin Obara <marcin_obara@users.sourceforge.net>
Cc: Marcel Selhorst <tpm@selhorst.net>
Cc: Kylene Jo Hall <kjhall@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9e5b1b12

drivers/char/tpm/tpm.c

+7 −0
Original line number Diff line number Diff line
@@ -557,6 +557,13 @@ void tpm_get_timeouts(struct tpm_chip *chip) 
	    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. So we

	 * fix up the resulting too-small TPM_SHORT value to make things work.

	 */

	if (chip->vendor.duration[TPM_SHORT] < (HZ/100))

		chip->vendor.duration[TPM_SHORT] = HZ;



	chip->vendor.duration[TPM_MEDIUM] =

	    usecs_to_jiffies(be32_to_cpu

			     (*((__be32 *) (data +