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| − | __TOC__
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| | {{Stub}} | | {{Stub}} |
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| − | == The ThinkPad Embedded Controller ==
| + | = The ThinkPad Embedded Controller = |
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| | This page contains information about Embedded Controller chips found in ThinkPads. | | This page contains information about Embedded Controller chips found in ThinkPads. |
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| | :Used on older ThinkPads, including the model 570, and maybe even earlier models. | | :Used on older ThinkPads, including the model 570, and maybe even earlier models. |
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| − | == Firmware issues == | + | = See also = |
| − | | + | * [[Embedded Controller Firmware|Embedded controler firmware information and bugs]] |
| − | Various bugs have been observed in the various ThinkPad EC firmwares. Most of them were fixed in later revisions,
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| − | but a few are either very dangerous and driver writers need to always work around them, or have never been fixed.
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| − | One must keep in mind that many of the bugs fixed by IBM or Lenovo could cause serious problems, but might never be noticed by driver developers, because they usually keep their ThinkPads up-to-date. People that don't keep their ThinkPad firmware up-to-date are excellent guinea pigs...
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| − | | |
| − | {{WARN|As a rule, if you are not using the latest available firmware for your ThinkPad, you are likely to be the unlucky chap that will find out some new code hits a firmware bug that was fixed by IBM or Lenovo. Do yourself a favour and always keep your ThinkPad's firmware up-to-date.}}
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| − | | |
| − | === Bug: Advanced battery query causes EC hang ===
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| − | * Severity: '''critical''' | |
| − | * Fix: available from IBM, but not for all affected models
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| − | * Information: [http://thread.gmane.org/gmane.linux.hardware.thinkpad/27484/ thread in linux-thinkpad ML]
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| − | | |
| − | * Models affected:
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| − | ** {{T40}}, {{T40p}}, {{T41}}, {{T41p}}, {{T42}}, {{T42p}}: all models affected, no fix available
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| − | ** {{T43}} 26xx, {{T43p}}: fixed on firmware 1YHT28WW (1.05) and newer
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| − | ** {{T43}} 18xx, {{R52}}: likely buggy, unknown status (might be fixed in latest firmwares)
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| − | ** other ThinkPads featuring advanced battery queries: unknown status; every model supported by [[tp_smapi]] advanced battery information is a candidate for this bug
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| − | | |
| − | The EC LPC3B advanced battery query function 0x0B (only used by [[tp_smapi]]) has a hideous bug that
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| − | causes the EC to misbehave and crash (usually hanging the entire ThinkPad). This function must never
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| − | be called on a buggy firmware.
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| − | | |
| − | === Bug: Fan control loop status is not initialized ===
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| − | * Severity: low
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| − | * Fix: unknown status at this time
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| − | * Information: [http://forum.thinkpads.com/viewforum.php?f=27 thinkpads.com fan control programs forum], [http://thread.gmane.org/gmane.linux.hardware.thinkpad/28326/ linux-thinkpad ML thread]
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| − | | |
| − | * Models affected:
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| − | ** {{T43}}, {{T43p}}, {{R52}}
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| − | ** no information about other models, please report on linux-thinkpad ML, see link above
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| − | | |
| − | The EC does not correctly initializes its 0x2f (fan control) register, so [[ibm-acpi]] cannot determine the
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| − | correct status of the fan control until something writes to the fan control register for the first time.
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| − | | |
| − | === Bug: Fan control loop pulses the fan in an annoying pattern ===
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| − | * Severity: low
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| − | * Fix: available from IBM, but incorrectly fixed on some models. Unofficial fix available for firmware hackers.
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| − | * Workaround: A software workaround is available using an [[ACPI fan control script]], but this overrides the embedded controller's fan control algorithm.
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| − | * Information: [http://forum.thinkpads.com/viewtopic.php?t=20958 thinkpads.com forum thread], [http://forum.thinkpads.com/viewtopic.php?t=1670 thinkpads.com forum thread], [[Problem with fan noise]]
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| − | | |
| − | * Models affected:
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| − | ** {{T40}}, {{T40p}}, {{T41}}, {{T41p}}, {{T42}}, {{T42p}}: fixed by firmware 1RHT70WW (3.03) and later
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| − | ** {{T43}}, {{T43p}}, {{R52}}: IBM provided a '''broken''' firmware fix, so they are all affected
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| − | ** other newer models: unknown status
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| − | | |
| − | The fan control loop will vary the fan speed quite a lot, in a very annoying pattern. The broken fix on
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| − | the T43 firmware causes annoying pulses every 30s.
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| − | | |
| − | === Bug: Tachometer registers not invalidated in disengaged mode ===
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| − | * Severity: low
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| − | * Fix: none available
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| − | | |
| − | * Models affected:
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| − | ** Nearly all ThinkPad models
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| − | | |
| − | When the fan control loop is placed in disengaged mode (bit 6 of EC register 0x2f is set) where no tachometer readings take place, the EC does not set the tachometer registers (0x84, 0x85) to 0xFF to signal an invalid reading. Instead, the registers are simply not updated anymore and retain the last tachometer reading that took place.
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| − | | |
| − | == See also ==
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| | * [[BIOS Upgrade|BIOS and firmware upgrade information]] | | * [[BIOS Upgrade|BIOS and firmware upgrade information]] |
| − | * [[tp_smapi|tp_smapi Linux driver]]
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| − | * [[ibm-acpi|ibm-acpi Linux ACPI driver]]
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| | [[Category:Components]] | | [[Category:Components]] |
