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authorStewart Smith <stewart@linux.ibm.com>2019-05-31 16:12:59 +1000
committerStewart Smith <stewart@linux.ibm.com>2019-06-03 10:20:00 +1000
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tree8005c86b1c0541ce1fbaeb36606381da26756328
parent39bd3717a128fddf27cae4422a8e1f6e31b226f1 (diff)
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skiboot 6.0.3 release notes
Signed-off-by: Stewart Smith <stewart@linux.ibm.com> (cherry picked from commit 8cdc58924f8d200e62bf91a57feb39f6f12e41d4) Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
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+.. _skiboot-6.0.3:
+
+=============
+skiboot-6.0.3
+=============
+
+skiboot 6.0.3 was released on Wednesday May 23rd, 2018. It replaces
+:ref:`skiboot-6.0.2` as the current stable release in the 6.0.x series.
+
+It is recommended that 6.0.3 be used instead of any previous 6.0.x version.
+
+Over :ref:`skiboot-6.0.3`, we have bug fixes related to i2c booting in
+secure mode, and general functionality with a TPM present. These changes are:
+
+- p8-i2c: Remove force reset
+
+ Force reset was added as an attempt to work around some issues with TPM
+ devices locking up their I2C bus. In that particular case the problem
+ was that the device would hold the SCL line down permanently due to a
+ device firmware bug. The force reset doesn't actually do anything to
+ alleviate the situation here, it just happens to reset the internal
+ master state enough to make the I2C driver appear to work until
+ something tries to access the bus again.
+
+ On P9 systems with secure boot enabled there is the added problem
+ of the "diagostic mode" not being supported on I2C masters A,B,C and
+ D. Diagnostic mode allows the SCL and SDA lines to be driven directly
+ by software. Without this force reset is impossible to implement.
+
+ This patch removes the force reset functionality entirely since:
+
+ a) it doesn't do what it's supposed to, and
+ b) it's butt ugly code
+
+ Additionally, turn p8_i2c_reset_engine() into p8_i2c_reset_port().
+ There's no need to reset every port on a master in response to an
+ error that occurred on a specific port.
+
+- libstb/i2c-driver: Bump max timeout
+
+ We have observed some TPMs clock streching the I2C bus for signifigant
+ amounts of time when processing commands. The same TPMs also have
+ errata that can result in permernantly locking up a bus in response to
+ an I2C transaction they don't understand. Using an excessively long
+ timeout to prevent this in the field.
+- Add TPM timeout workaround
+
+ Set the default timeout for any bus containing a TPM to one second. This
+ is needed to work around a bug in the firmware of certain TPMs that will
+ clock strech the I2C port the for up to a second. Additionally, when the
+ TPM is clock streching it responds to a STOP condition on the bus by
+ bricking itself. Clearing this error requires a hard power cycle of the
+ system since the TPM is powered by standby power.