Red Hat Bugzilla – Bug 196862
Make 8250_pci as a kernel module
Last modified: 2012-06-20 11:54:02 EDT
Description of problem:
It is not a bug. It is enhancement request. Our vendor (Multitech) requires to
recompile kernel in order to make 8250_pci as a module. We have to do it just
to use fax boards. Could this change be incorporated into streamline release
because any kernel recompilation voids support from other vendors.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
It is built-in kernel module
Required to be loadable kernel module
here is the link about Multitech driver:
Just to clarify here, your asking to change the config from
"CONFIG_SERIAL_8250=y" to "CONFIG_SERIAL_8250=m"?
Yes, this is what MultiTech is asking to do
Just to clarify a bit further.... The reason for this request is to be able to
compile a seperate module for the 8250 serial so as to be able to use it with
the supported kernel? I.e the expectation is to be able to "make modules ; make
modules_install" and not have to re-compile the entire kernel (which would then
be an unspported kernel)?
Yes. As per documentation from MultiTech:
"...Observations / Known Issues:
- In Case of Red Hat Distributions, Kernel version 2.6.8 and above has the
8250_pci driver built into the Kernel and therefore the MultiTech ISIUPCI
driver will fail to load. The Kernel has to be re-compiled with the option
set to 8250_pci being loaded as a module.
Procedure for Kernel Re-compilation:
- Change the working directory to /usr/src/linux-xxxx.
- Execute "make mrproper"
- Execute "make menuconfig" or "make xconfig"
- Follow the link device drivers-> character devices-> Serial drivers ->
----Make "8250/16550 and compatible serial support" as module (M instead of *
must be seen on the square bracket)
----Disable "Extended 8250/16550 serial driver options"
- Execute "make modules"
- Execute "make modules_install"
- Execute "make install"
The above process could take some time (possibly upto an hour) Reboot the
system with the newly compiled Kernel and you should be able to install the
mtsi_upci driver to support ISIxxxx_UPCI cards."
If 8250 would be a kernel module then it will be much simpler to administer
the system when Red Hat releases new kernel - just up2date and run MultiTech
script to compile new module = quick and easy.
Hope this answers your question,
This change (to build 8250_pci as a module) was reviewed by engineering but
rejected because it may cause reverts and other suprises for other customers
that assume its built in
A more favored approach would be to sort this out upstream (i.e. if PCI idents
need to be added). If the hardware isnt detected try using 'setserial' to
resolve address conflicts as mentioned in Comment #10.
Thank you for submitting this issue for consideration in Red Hat Enterprise Linux. The release for which you requested us to review is now End of Life.
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