[LITMUS^RT] LITMUS^RT Compilation

[Pratyush Patel]

That makes sense, thank you!

On Tue, Jan 26, 2016 at 4:17 AM, Björn Brandenburg <bbb at mpi-sws.org> wrote:
>> On 25 Jan 2016, at 08:50, Pratyush Patel <pratyushpatel.1995 at gmail.com> wrote:
>>
>> This may be unrelated to LITMUS^RT and is perhaps due to something I
>> am failing to notice, or a very unlikely Linux compilation bug, but I
>> decided to post it here as the error only occurs when the LITMUS^RT
>> patch is applied to Linux 4.1.3 while keeping the configuration same.
>>
>> As for background, I am trying out the latest stable LITMUS^RT patch
>> (2015.1), by compiling the kernel on Ubuntu 15.10. I ran into a
>> compilation error while running "make modules", as attached in this
>> email. After some browsing on the mailing-list archives, I noticed the
>> same compilation error was reported here:
>>
>> https://lists.litmus-rt.org/pipermail/litmus-dev/2015/001177.html
>>
>> However, I am able to successfully compile the base Linux kernel 4.1.3
>> using essentially the same config, and I have attached the config
>> files diff for reference. Curiously, this config does not result in
>> the stdout message,
>>
>> CC[M]    drivers/media/usb/as102/as102_usb_drv.o
>>
>> during the make process of 4.1.3, but does so after the patch,
>> indicating that somehow... the same module is not compiled for the
>> base kernel with the same config. I understand that the LITMUS patch
>> does not make changes to this specific driver module, but any ideas as
>> to what might be causing this strange behaviour?
>>
>> I believe it may be of relevance to mention that disabling
>> CONFIG_DVB_AS102 and CONFIG_DVB_AS102_FE lets me compile and install
>> LITMUS^RT successfully. Any insight would be much appreciated!
>
> Hi Pratyush,
>
> I took a look at the code in question, reproduced below:
>
>>         if (recv_buf != NULL) {
>> #ifdef TRACE
>>                 dev_dbg(bus_adap->usb_dev->dev,
>>                         "want to read: %d bytes\n", recv_buf_len);
>> #endif
>
> The problem is that the code is somehow pulling in our TRACE() debugging macro, which then makes the #ifdef evaluate to true. Classic result of C's lack of namespaces…
>
> You could just hack in an "#undef TRACE" at the top of the file.
>
> Or disable the module, given that it’s the driver for "Abilis Systems Single DVB-T Receiver” (unless you wanted to watch TV with LITMUS^RT… ;-).
>
> - Björn
>
>
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