[PATCH] staging: rtl8723bs: Remove ACPI table declaration

[PATCH] staging: rtl8723bs: Remove ACPI table declaration

[Nathan Chancellor]

Clang warns that the acpi_id declaration is not going to be emitted
in the final assembly:

drivers/staging/rtl8723bs/os_dep/sdio_intf.c:25:36: warning: variable
'acpi_ids' is not needed and will not be emitted
[-Wunneeded-internal-declaration]
static const struct acpi_device_id acpi_ids[] = {
                                   ^
1 warning generated.

This is because it's marked as static const and it is not used anywhere
in this file. Doing a git grep on this driver for 'acpi' shows that this
declaration has been unused since the driver's initial induction. Remove
it since it's not doing anything.

Link: https://github.com/ClangBuiltLinux/linux/issues/169
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/staging/rtl8723bs/os_dep/sdio_intf.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
index 6d02904de63f..d473f9bd08c3 100644
--- a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
+++ b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
@@ -22,13 +22,7 @@ static const struct sdio_device_id sdio_ids[] =
 	{ SDIO_DEVICE(0x024c, 0xb723), },
 	{ /* end: all zeroes */				},
 };
-static const struct acpi_device_id acpi_ids[] = {
-	{"OBDA8723", 0x0000},
-	{}
-};
-
 MODULE_DEVICE_TABLE(sdio, sdio_ids);
-MODULE_DEVICE_TABLE(acpi, acpi_ids);
 
 static int rtw_drv_init(struct sdio_func *func, const struct sdio_device_id *id);
 static void rtw_dev_remove(struct sdio_func *func);
-- 
2.19.0

Re: [PATCH] staging: rtl8723bs: Remove ACPI table declaration

[Greg Kroah-Hartman]

On Tue, Sep 25, 2018 at 10:39:10PM -0700, Nathan Chancellor wrote:
> Clang warns that the acpi_id declaration is not going to be emitted
> in the final assembly:
> 
> drivers/staging/rtl8723bs/os_dep/sdio_intf.c:25:36: warning: variable
> 'acpi_ids' is not needed and will not be emitted
> [-Wunneeded-internal-declaration]
> static const struct acpi_device_id acpi_ids[] = {
>                                    ^
> 1 warning generated.
> 
> This is because it's marked as static const and it is not used anywhere
> in this file. Doing a git grep on this driver for 'acpi' shows that this
> declaration has been unused since the driver's initial induction. Remove
> it since it's not doing anything.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/169
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  drivers/staging/rtl8723bs/os_dep/sdio_intf.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> index 6d02904de63f..d473f9bd08c3 100644
> --- a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> +++ b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> @@ -22,13 +22,7 @@ static const struct sdio_device_id sdio_ids[] =
>  	{ SDIO_DEVICE(0x024c, 0xb723), },
>  	{ /* end: all zeroes */				},
>  };
> -static const struct acpi_device_id acpi_ids[] = {
> -	{"OBDA8723", 0x0000},
> -	{}
> -};
> -
>  MODULE_DEVICE_TABLE(sdio, sdio_ids);
> -MODULE_DEVICE_TABLE(acpi, acpi_ids);

You just removed the ability for the driver to be automatically loaded
if that acpi id is present.

Not good :(

I think you need to fix up your scripts, this is valid code...

greg k-h

Re: [PATCH] staging: rtl8723bs: Remove ACPI table declaration

[Nathan Chancellor]

On Wed, Sep 26, 2018 at 08:22:45AM +0200, Greg Kroah-Hartman wrote:
> On Tue, Sep 25, 2018 at 10:39:10PM -0700, Nathan Chancellor wrote:
> > Clang warns that the acpi_id declaration is not going to be emitted
> > in the final assembly:
> > 
> > drivers/staging/rtl8723bs/os_dep/sdio_intf.c:25:36: warning: variable
> > 'acpi_ids' is not needed and will not be emitted
> > [-Wunneeded-internal-declaration]
> > static const struct acpi_device_id acpi_ids[] = {
> >                                    ^
> > 1 warning generated.
> > 
> > This is because it's marked as static const and it is not used anywhere
> > in this file. Doing a git grep on this driver for 'acpi' shows that this
> > declaration has been unused since the driver's initial induction. Remove
> > it since it's not doing anything.
> > 
> > Link: https://github.com/ClangBuiltLinux/linux/issues/169
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > ---
> >  drivers/staging/rtl8723bs/os_dep/sdio_intf.c | 6 ------
> >  1 file changed, 6 deletions(-)
> > 
> > diff --git a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > index 6d02904de63f..d473f9bd08c3 100644
> > --- a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > +++ b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > @@ -22,13 +22,7 @@ static const struct sdio_device_id sdio_ids[] =
> >  	{ SDIO_DEVICE(0x024c, 0xb723), },
> >  	{ /* end: all zeroes */				},
> >  };
> > -static const struct acpi_device_id acpi_ids[] = {
> > -	{"OBDA8723", 0x0000},
> > -	{}
> > -};
> > -
> >  MODULE_DEVICE_TABLE(sdio, sdio_ids);
> > -MODULE_DEVICE_TABLE(acpi, acpi_ids);
> 
> You just removed the ability for the driver to be automatically loaded
> if that acpi id is present.
> 

I am not sure I understand. Every instance of acpi_device_id that I
looked at in the kernel before sending this patch uses MODULE_DEVICE_TABLE
but then that acpi_device_id declaration is always used in the driver
definition either under the acpi_match_table member or ids member
depending on what type of driver it is. Should this one do that as well?
Is that even possible with an sdio driver? I apologize if I am not
making sense, I'm not super familiar with these interfaces.

I also read 'Documentation/acpi/enumeration.txt' which makes it seem
like the declaration needs to be added to the device definition as well.

> Not good :(
> 
> I think you need to fix up your scripts, this is valid code...
> 

No scripts here, just a human interpreting warnings manually.

> greg k-h

Thanks for the review,
Nathan

Re: [PATCH] staging: rtl8723bs: Remove ACPI table declaration

[Greg Kroah-Hartman]

On Tue, Sep 25, 2018 at 11:44:37PM -0700, Nathan Chancellor wrote:
> On Wed, Sep 26, 2018 at 08:22:45AM +0200, Greg Kroah-Hartman wrote:
> > On Tue, Sep 25, 2018 at 10:39:10PM -0700, Nathan Chancellor wrote:
> > > Clang warns that the acpi_id declaration is not going to be emitted
> > > in the final assembly:
> > > 
> > > drivers/staging/rtl8723bs/os_dep/sdio_intf.c:25:36: warning: variable
> > > 'acpi_ids' is not needed and will not be emitted
> > > [-Wunneeded-internal-declaration]
> > > static const struct acpi_device_id acpi_ids[] = {
> > >                                    ^
> > > 1 warning generated.
> > > 
> > > This is because it's marked as static const and it is not used anywhere
> > > in this file. Doing a git grep on this driver for 'acpi' shows that this
> > > declaration has been unused since the driver's initial induction. Remove
> > > it since it's not doing anything.
> > > 
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/169
> > > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > > ---
> > >  drivers/staging/rtl8723bs/os_dep/sdio_intf.c | 6 ------
> > >  1 file changed, 6 deletions(-)
> > > 
> > > diff --git a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > > index 6d02904de63f..d473f9bd08c3 100644
> > > --- a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > > +++ b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > > @@ -22,13 +22,7 @@ static const struct sdio_device_id sdio_ids[] =
> > >  	{ SDIO_DEVICE(0x024c, 0xb723), },
> > >  	{ /* end: all zeroes */				},
> > >  };
> > > -static const struct acpi_device_id acpi_ids[] = {
> > > -	{"OBDA8723", 0x0000},
> > > -	{}
> > > -};
> > > -
> > >  MODULE_DEVICE_TABLE(sdio, sdio_ids);
> > > -MODULE_DEVICE_TABLE(acpi, acpi_ids);
> > 
> > You just removed the ability for the driver to be automatically loaded
> > if that acpi id is present.
> > 
> 
> I am not sure I understand. Every instance of acpi_device_id that I
> looked at in the kernel before sending this patch uses MODULE_DEVICE_TABLE
> but then that acpi_device_id declaration is always used in the driver
> definition either under the acpi_match_table member or ids member
> depending on what type of driver it is. Should this one do that as well?

I don't know, but it's not always necessary.

> Is that even possible with an sdio driver? I apologize if I am not
> making sense, I'm not super familiar with these interfaces.
> 
> I also read 'Documentation/acpi/enumeration.txt' which makes it seem
> like the declaration needs to be added to the device definition as well.

If it is a real acpi driver, yes, you need to actually register it with
the acpi core.

But, if it is just using the auto-load functionality of "if this acpi
string is found, load the module!" then the code is correct as-is.

Yeah, it's a hack, but does work and helps out for auto-loading drivers
for "odd" hardware that is not always self-describing.

thanks,

greg k-h

Re: [PATCH] staging: rtl8723bs: Remove ACPI table declaration

[Nathan Chancellor]

On Wed, Sep 26, 2018 at 08:49:15AM +0200, Greg Kroah-Hartman wrote:
> On Tue, Sep 25, 2018 at 11:44:37PM -0700, Nathan Chancellor wrote:
> > On Wed, Sep 26, 2018 at 08:22:45AM +0200, Greg Kroah-Hartman wrote:
> > > On Tue, Sep 25, 2018 at 10:39:10PM -0700, Nathan Chancellor wrote:
> > > > Clang warns that the acpi_id declaration is not going to be emitted
> > > > in the final assembly:
> > > > 
> > > > drivers/staging/rtl8723bs/os_dep/sdio_intf.c:25:36: warning: variable
> > > > 'acpi_ids' is not needed and will not be emitted
> > > > [-Wunneeded-internal-declaration]
> > > > static const struct acpi_device_id acpi_ids[] = {
> > > >                                    ^
> > > > 1 warning generated.
> > > > 
> > > > This is because it's marked as static const and it is not used anywhere
> > > > in this file. Doing a git grep on this driver for 'acpi' shows that this
> > > > declaration has been unused since the driver's initial induction. Remove
> > > > it since it's not doing anything.
> > > > 
> > > > Link: https://github.com/ClangBuiltLinux/linux/issues/169
> > > > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > > > ---
> > > >  drivers/staging/rtl8723bs/os_dep/sdio_intf.c | 6 ------
> > > >  1 file changed, 6 deletions(-)
> > > > 
> > > > diff --git a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > > > index 6d02904de63f..d473f9bd08c3 100644
> > > > --- a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > > > +++ b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> > > > @@ -22,13 +22,7 @@ static const struct sdio_device_id sdio_ids[] =
> > > >  	{ SDIO_DEVICE(0x024c, 0xb723), },
> > > >  	{ /* end: all zeroes */				},
> > > >  };
> > > > -static const struct acpi_device_id acpi_ids[] = {
> > > > -	{"OBDA8723", 0x0000},
> > > > -	{}
> > > > -};
> > > > -
> > > >  MODULE_DEVICE_TABLE(sdio, sdio_ids);
> > > > -MODULE_DEVICE_TABLE(acpi, acpi_ids);
> > > 
> > > You just removed the ability for the driver to be automatically loaded
> > > if that acpi id is present.
> > > 
> > 
> > I am not sure I understand. Every instance of acpi_device_id that I
> > looked at in the kernel before sending this patch uses MODULE_DEVICE_TABLE
> > but then that acpi_device_id declaration is always used in the driver
> > definition either under the acpi_match_table member or ids member
> > depending on what type of driver it is. Should this one do that as well?
> 
> I don't know, but it's not always necessary.
> 
> > Is that even possible with an sdio driver? I apologize if I am not
> > making sense, I'm not super familiar with these interfaces.
> > 
> > I also read 'Documentation/acpi/enumeration.txt' which makes it seem
> > like the declaration needs to be added to the device definition as well.
> 
> If it is a real acpi driver, yes, you need to actually register it with
> the acpi core.
> 
> But, if it is just using the auto-load functionality of "if this acpi
> string is found, load the module!" then the code is correct as-is.
> 
> Yeah, it's a hack, but does work and helps out for auto-loading drivers
> for "odd" hardware that is not always self-describing.
> 
> thanks,
> 
> greg k-h

Thank you for the explanation, I appreciate that and I'll keep it in
mind should I run across this kind of warning in the future. I'll send a
v2 now that silences this warning through the '__maybe_unused' attribute
like a few other commits that deal with this warning.

Nathan