Ping-Ke Shih b68c7af0b2 rtlwifi: cleanup 8723be ant_sel definition
commit af8a41cccf8f469165c6debc8fe07c5fd2ca501a upstream.

Some HP laptops have only a single wifi antenna. This would not be a
problem except that they were shipped with an incorrectly encoded
EFUSE. It should have been possible to open the computer and transfer
the antenna connection to the other terminal except that such action
might void the warranty, and moving the antenna broke the Windows
driver. The fix was to add a module option that would override the
EFUSE encoding. That was done with commit c18d8f509571 ("rtlwifi:
rtl8723be: Add antenna select module parameter"). There was still a
problem with Bluetooth coexistence, which was addressed with commit
baa170229095 ("rtlwifi: btcoexist: Implement antenna selection").
There were still problems, thus there were commit 0ff78adeef11
("rtlwifi: rtl8723be: fix ant_sel code") and commit 6d6226928369
("rtlwifi: btcoexist: Fix antenna selection code"). Despite all these
attempts at fixing the problem, the code is not yet right. A proper
fix is important as there are now instances of laptops having
RTL8723DE chips with the same problem.

The module parameter ant_sel is used to control antenna number and path.
At present enum ANT_{X2,X1} is used to define the antenna number, but
this choice is not intuitive, thus change to a new enum ANT_{MAIN,AUX}
to make it more readable. This change showed examples where incorrect
values were used. It was also possible to remove a workaround in
halbtcoutsrc.c.

The experimental results with single antenna connected to specific path
are now as follows:
  ant_sel  ANT_MAIN(#1)  ANT_AUX(#2)
     0        -8            -62
     1        -62           -10
     2        -6            -60

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Fixes: c18d8f509571 ("rtlwifi: rtl8723be: Add antenna select module parameter")
Fixes: baa170229095 ("rtlwifi: btcoexist: Implement antenna selection")
Fixes: 0ff78adeef11 ("rtlwifi: rtl8723be: fix ant_sel code")
Fixes: 6d6226928369 ("rtlwifi: btcoexist: Fix antenna selection code")
Cc: Stable <stable@vger.kernel.org> # 4.7+
Reviewed-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-09 09:51:51 +02:00
2018-05-01 12:58:07 -07:00
2018-05-09 09:51:50 +02:00
2018-05-01 12:58:27 -07:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

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.
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