Re: [PATCH] perf: fix 'make help' message error

[Jianyu Zhan <nasa4836@gmail.com>]

Hi, Namhyung,

>I don't know what's the correct way to do this.  But it seems like the
>prefix was overwritten when given from user, so below patch will work
>also.

This does work too. So I update the patch as below:

---8<---
From: Jianyu Zhan <nasa4836@gmail.com>
Date: Sat, 24 May 2014 22:34:26 +0800
Subject: [PATCH] perf: fix 'make help' message error

Currently 'make help' message has such hint:

   use "make prefix=<path> <install target>" to install to a particular
       path like make prefix=/usr/local install install-doc

But this is misleading, when I specify "prefix=/usr/local", it has got no
respect at all.

This is because that, "DESTDIR" is condiered first. In this case, "DESTDIR"
has an empty value, so "prefix" is honored. However, "prefix" is unconditionally
assigned to $HOME, regardless of what it is set to from command line. So our
"prefix" setting got no respect and the actual destination falls back to $HOME.

This patch fixes this issue and corrects the help message.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
---
 tools/perf/Makefile.perf   | 4 ++--
 tools/perf/config/Makefile | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 895edd3..5918063 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -784,8 +784,8 @@ help:
 	@echo ''
 	@echo 'Perf install targets:'
 	@echo '  NOTE: documentation build requires asciidoc, xmlto packages to be installed'
-	@echo '  HINT: use "make prefix=<path> <install target>" to install to a particular'
-	@echo '        path like make prefix=/usr/local install install-doc'
+	@echo '  HINT: use "prefix" or "DESTDIR" to install to a particular'
+	@echo '        path like "make prefix=/usr/local install install-doc"'
 	@echo '  install	- install compiled binaries'
 	@echo '  install-doc	- install *all* documentation'
 	@echo '  install-man	- install manpage documentation'
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index 802cf54..53dc11e 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -601,7 +601,7 @@ endif
 
 # Make the path relative to DESTDIR, not to prefix
 ifndef DESTDIR
-prefix = $(HOME)
+prefix ?= $(HOME)
 endif
 bindir_relative = bin
 bindir = $(prefix)/$(bindir_relative)
-- 
2.0.0