title: Patching and compiling kernel, in which directory
body: <p>I'm trying to apply a patch to my kernel source with limited success. The target machine is really some ARM device, but I haven't compiled a kernel before so I thought I'd start with an x86_64 kernel. This has been only marginally easier :)</p>
  
  <p>Now, according to some tutorials, it seemed like we should use the source in <code>/usr/src/linux-something</code>. But when I tried to patch there I got </p>
  
  <pre><code>File Documentation/sysrq.txt is read-only; trying to patch anyway
  patch: **** Can't create temporary file Documentation/sysrq.txt.oG1oiZW : Permission denied
  </code></pre>
  
  <p>even under sudo. So I tried just copying the patch and the linux source folder to my home directory and patched it from there. This worked. Why is this and will this have any weird side effects when compiling?</p>