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7781edaed6
Unfortunately some DSDTs issue bogus i2c reads to non existing devices
resulting in -EREMOTEIO errors because the non existing device of course
does not ack.
This happens e.g. from the The Asus T100TA's _BIX method, the DSDT on
the T100TA defines 2 resources on the I2C1 bus:
Name (EHID, ResourceTemplate ()
{
I2cSerialBusV2 (0x005B, ControllerInitiated, 0x00061A80,
AddressingMode7Bit, "\\_SB.I2C1",
0x00, ResourceConsumer, , Exclusive,
)
})
OperationRegion (EHOR, GenericSerialBus, Zero, 0x0100)
Field (EHOR, BufferAcc, NoLock, Preserve)
{
Connection (EHID),
Offset (0x01),
AccessAs (BufferAcc, AttribBytes (0x10)),
ABCD, 8
}
Name (UMPC, ResourceTemplate ()
{
I2cSerialBusV2 (0x0066, ControllerInitiated, 0x00061A80,
AddressingMode7Bit, "\\_SB.I2C1",
0x00, ResourceConsumer, , Exclusive,
)
})
The _BIX method does a single read (on each BIX() call) from the EHID
device through the ABCD Field, only to completely ignore the result.
This read always fails as there is no i2c client at address 0x5b.
The _BIX method also does several reads from the UMPC device and actually
uses the results of those to provide battery information.
IIRC I've also seen some DSTDs which do an i2c read to detect if a device
is present, also leading to false positive errors being logged.
Esp. the _BIX use is problematic as the _BIX method gets called
periodically to monitor battery status.
This commit stops the logs from filling up with errors like these:
[ 57.327858] i2c i2c-0: i2c read 16 bytes from client@0x5b starting at
reg 0x1 failed, error: -121
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.