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Date: Thu, 17 Dec 2015 14:09:43 -0200
From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
To: Mason <slash.tmp@free.fr>
Cc: linux-media <linux-media@vger.kernel.org>,
	Hans Verkuil <hans.verkuil@cisco.com>
Subject: Re: Automatic device driver back-porting with media_build
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Em Thu, 17 Dec 2015 16:32:54 +0100
Mason <slash.tmp@free.fr> escreveu:

> On 17/12/2015 15:55, Mauro Carvalho Chehab wrote:
> 
> > Em Thu, 17 Dec 2015 15:30:43 +0100
> > Mason <slash.tmp@free.fr> escreveu:
> > 
> >> On 17/12/2015 15:08, Mauro Carvalho Chehab wrote:
> >>
> >>> Then I guess you're not using vanilla 3.4 Kernel, but some heavily
> >>> modified version. You're on your own here.
> >>
> >> #ifdef NEED_KVFREE
> >> #include <linux/mm.h>
> >> static inline void kvfree(const void *addr)
> >> {
> >> 	if (is_vmalloc_addr(addr))
> >> 		vfree(addr);
> >> 	else
> >> 		kfree(addr);
> >> }
> >> #endif
> >>
> >> /tmp/sandbox/media_build/v4l/compat.h: In function 'kvfree':
> >> /tmp/sandbox/media_build/v4l/compat.h:1631:3: error: implicit declaration of function 'vfree' [-Werror=implicit-function-declaration]
> >>    vfree(addr);
> >>    ^
> >>
> >> vfree is declared in linux/vmalloc.h
> >>
> >> The fix is trivial:
> >>
> >> diff --git a/v4l/compat.h b/v4l/compat.h
> >> index c225c07d6caa..7f3f1d5f9d11 100644
> >> --- a/v4l/compat.h
> >> +++ b/v4l/compat.h
> >> @@ -1625,6 +1625,7 @@ static inline void eth_zero_addr(u8 *addr)
> >>  
> >>  #ifdef NEED_KVFREE
> >>  #include <linux/mm.h>
> >> +#include <linux/vmalloc.h>
> >>  static inline void kvfree(const void *addr)
> >>  {
> >>         if (is_vmalloc_addr(addr))
> >>
> >>
> > 
> > Well, it doesn't hurt to add it to the media_build tree, since
> > vmalloc.h exists at least since 2.6.11.
> > 
> > Added upstream.
> > 
> > Did the driver compile fine?
> 
> I wanted to fix the NEED_WRITEL_RELAXED warning, but I don't know Perl.
> 
> v4l/scripts/make_config_compat.pl
> 
> check_files_for_func("writel_relaxed", "NEED_WRITEL_RELAXED", "include/asm-generic/io.h");
> incorrectly outputs
> #define NEED_WRITEL_RELAXED 1
> 
> 
> In file included from <command-line>:0:0:
> /tmp/sandbox/media_build/v4l/compat.h:1568:0: warning: "writel_relaxed" redefined
>  #define writel_relaxed writel
>  ^
> In file included from include/linux/scatterlist.h:10:0,
>                  from /tmp/sandbox/media_build/v4l/compat.h:1255,
>                  from <command-line>:0:
> /tmp/sandbox/custom-linux-3.4/arch/arm/include/asm/io.h:235:0: note: this is the location of the previous definition
>  #define writel_relaxed(v,c) ((void)__raw_writel((__force u32) \
>  ^
> 
> Shouldn't the script examine arch/$ARCH/include/asm/io.h instead of
> include/asm-generic/io.h ? (Or perhaps both?)
> 
> Does make_config_compat.pl know about ARCH?

No to both. When you do a "make init" on the Kernel repository, it
will evaluate the ARCH vars.

This is also needed for the media build to work, as it needs to
check what CONFIG vars are enabled on the targeted Kernel.

> 
> The following patch makes "#define NEED_WRITEL_RELAXED 1" go away,
> but I'm looking for a general solution.
> 
> 
> The next error is:
> 
>   CC [M]  /tmp/sandbox/media_build/v4l/dvb_net.o
> /tmp/sandbox/media_build/v4l/dvb_net.c: In function 'dvb_net_add_if':
> /tmp/sandbox/media_build/v4l/dvb_net.c:1244:38: error: macro "alloc_netdev" passed 4 arguments, but takes just 3
>        NET_NAME_UNKNOWN, dvb_net_setup);
>                                       ^
> /tmp/sandbox/media_build/v4l/dvb_net.c:1243:8: error: 'alloc_netdev' undeclared (first use in this function)
>   net = alloc_netdev(sizeof(struct dvb_net_priv), "dvb",
>         ^
> /tmp/sandbox/media_build/v4l/dvb_net.c:1243:8: note: each undeclared identifier is reported only once for each function it appears in
> /tmp/sandbox/media_build/v4l/dvb_net.c: At top level:
> /tmp/sandbox/media_build/v4l/dvb_net.c:1205:13: warning: 'dvb_net_setup' defined but not used [-Wunused-function]
>  static void dvb_net_setup(struct net_device *dev)
> 
> Will look into it.

As I said before, heavily patched Kernel. It seems that the network stack
was updated to some newer version. The media_build backport considers
only the upstream Kernels. In the specific case of 3.4, it is known
to build fine with Kernel linux-3.4.27. See:
	http://hverkuil.home.xs4all.nl/logs/Wednesday.log


Regards,
Mauro



> 
> 
> Regards.
> 
> diff --git a/v4l/scripts/make_config_compat.pl b/v4l/scripts/make_config_compat.pl
> index 641f55e9c137..30a004525c08 100644
> --- a/v4l/scripts/make_config_compat.pl
> +++ b/v4l/scripts/make_config_compat.pl
> @@ -664,7 +664,7 @@ sub check_other_dependencies()
>         check_files_for_func("DMA_ATTR_SKIP_CPU_SYNC", "NEED_DMA_ATTR_SKIP_CPU_SYNC", "include/linux/dma-attrs.h");
>         check_files_for_func("sign_extend32", "NEED_SIGN_EXTEND32", "include/linux/bitops.h");
>         check_files_for_func("netdev_dbg", "NEED_NETDEV_DBG", "include/linux/netdevice.h");
> -       check_files_for_func("writel_relaxed", "NEED_WRITEL_RELAXED", "include/asm-generic/io.h");
> +       check_files_for_func("writel_relaxed", "NEED_WRITEL_RELAXED", "arch/arm/include/asm/io.h");
>         check_files_for_func("get_user_pages_unlocked", "NEED_GET_USER_PAGES_UNLOCKED", "include/linux/mm.h");
>         check_files_for_func("pr_warn_once", "NEED_PR_WARN_ONCE", "include/linux/printk.h");
>         check_files_for_func("DIV_ROUND_CLOSEST_ULL", "NEED_DIV_ROUND_CLOSEST_ULL", "include/linux/kernel.h");
> 
>