Cleanup of -Wunused-const-variable in drivers/usb/host/xhci-tegra.c

Cleanup of -Wunused-const-variable in drivers/usb/host/xhci-tegra.c

[Nathan Huckleberry]

Hey all,

I'm looking into cleaning up ignored warnings in the kernel so we can
remove compiler flags to ignore warnings.

There's an unused variable ('mbox_cmd_name') in xhci-tegra.c. Looks
like it was intended for logging or debugging, but never used. Just
wanted to reach out to ask the best steps for cleaning this up.

If the variable is no longer needed I'd like to send a patch to remove it.

https://github.com/ClangBuiltLinux/linux/issues/533

Thanks,
Nathan Huckleberry

Re: Cleanup of -Wunused-const-variable in drivers/usb/host/xhci-tegra.c

[Greg KH]

On Thu, Jun 13, 2019 at 11:38:38AM -0700, Nathan Huckleberry wrote:
> Hey all,
> 
> I'm looking into cleaning up ignored warnings in the kernel so we can
> remove compiler flags to ignore warnings.
> 
> There's an unused variable ('mbox_cmd_name') in xhci-tegra.c. Looks
> like it was intended for logging or debugging, but never used. Just
> wanted to reach out to ask the best steps for cleaning this up.
> 
> If the variable is no longer needed I'd like to send a patch to remove it.

You never have to ask permission to send a patch :)

[PATCH] usb: host: xhci-tegra: Fix Wunused-const-variable

[Nathan Huckleberry]

Clang produces the following warning

drivers/usb/host/xhci-tegra.c:357:27: warning: unused variable
'mbox_cmd_name' [-Wunused-const-variable]
static const char * const mbox_cmd_name[] = {

Looks like it was intended for logging or debugging, but was
never implemented. Removing mbox_cmd_name.

Cc: clang-built-linux@googlegroups.com
Link: https://github.com/ClangBuiltLinux/linux/issues/533
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
---
 drivers/usb/host/xhci-tegra.c | 23 -----------------------
 1 file changed, 23 deletions(-)

diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index 294158113d62..dafc65911fc0 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -354,29 +354,6 @@ enum tegra_xusb_mbox_cmd {
 	MBOX_CMD_NAK
 };
 
-static const char * const mbox_cmd_name[] = {
-	[  1] = "MSG_ENABLE",
-	[  2] = "INC_FALCON_CLOCK",
-	[  3] = "DEC_FALCON_CLOCK",
-	[  4] = "INC_SSPI_CLOCK",
-	[  5] = "DEC_SSPI_CLOCK",
-	[  6] = "SET_BW",
-	[  7] = "SET_SS_PWR_GATING",
-	[  8] = "SET_SS_PWR_UNGATING",
-	[  9] = "SAVE_DFE_CTLE_CTX",
-	[ 10] = "AIRPLANE_MODE_ENABLED",
-	[ 11] = "AIRPLANE_MODE_DISABLED",
-	[ 12] = "START_HSIC_IDLE",
-	[ 13] = "STOP_HSIC_IDLE",
-	[ 14] = "DBC_WAKE_STACK",
-	[ 15] = "HSIC_PRETEND_CONNECT",
-	[ 16] = "RESET_SSPI",
-	[ 17] = "DISABLE_SS_LFPS_DETECTION",
-	[ 18] = "ENABLE_SS_LFPS_DETECTION",
-	[128] = "ACK",
-	[129] = "NAK",
-};
-
 struct tegra_xusb_mbox_msg {
 	u32 cmd;
 	u32 data;
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog

Re: [PATCH] usb: host: xhci-tegra: Fix Wunused-const-variable

[Thierry Reding]

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On Thu, Jun 13, 2019 at 11:58:38AM -0700, Nathan Huckleberry wrote:
> Clang produces the following warning
> 
> drivers/usb/host/xhci-tegra.c:357:27: warning: unused variable
> 'mbox_cmd_name' [-Wunused-const-variable]
> static const char * const mbox_cmd_name[] = {
> 
> Looks like it was intended for logging or debugging, but was
> never implemented. Removing mbox_cmd_name.
> 
> Cc: clang-built-linux@googlegroups.com
> Link: https://github.com/ClangBuiltLinux/linux/issues/533
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>
> ---
>  drivers/usb/host/xhci-tegra.c | 23 -----------------------
>  1 file changed, 23 deletions(-)

I wonder why we're not seeing this with regular GCC builds. This code
has been in the kernel for a long time. Oh... looking at the git log, I
see that -Wunused-const-variable was moved to W=1 about 3 years ago, so
these are no longer showing up by default. That would explain it.

Anyway:

Acked-by: Thierry Reding <treding@nvidia.com>

> diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
> index 294158113d62..dafc65911fc0 100644
> --- a/drivers/usb/host/xhci-tegra.c
> +++ b/drivers/usb/host/xhci-tegra.c
> @@ -354,29 +354,6 @@ enum tegra_xusb_mbox_cmd {
>  	MBOX_CMD_NAK
>  };
>  
> -static const char * const mbox_cmd_name[] = {
> -	[  1] = "MSG_ENABLE",
> -	[  2] = "INC_FALCON_CLOCK",
> -	[  3] = "DEC_FALCON_CLOCK",
> -	[  4] = "INC_SSPI_CLOCK",
> -	[  5] = "DEC_SSPI_CLOCK",
> -	[  6] = "SET_BW",
> -	[  7] = "SET_SS_PWR_GATING",
> -	[  8] = "SET_SS_PWR_UNGATING",
> -	[  9] = "SAVE_DFE_CTLE_CTX",
> -	[ 10] = "AIRPLANE_MODE_ENABLED",
> -	[ 11] = "AIRPLANE_MODE_DISABLED",
> -	[ 12] = "START_HSIC_IDLE",
> -	[ 13] = "STOP_HSIC_IDLE",
> -	[ 14] = "DBC_WAKE_STACK",
> -	[ 15] = "HSIC_PRETEND_CONNECT",
> -	[ 16] = "RESET_SSPI",
> -	[ 17] = "DISABLE_SS_LFPS_DETECTION",
> -	[ 18] = "ENABLE_SS_LFPS_DETECTION",
> -	[128] = "ACK",
> -	[129] = "NAK",
> -};
> -
>  struct tegra_xusb_mbox_msg {
>  	u32 cmd;
>  	u32 data;
> -- 
> 2.22.0.rc2.383.gf4fbbf30c2-goog
> 

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Re: Cleanup of -Wunused-const-variable in drivers/usb/host/xhci-tegra.c

[Thierry Reding]

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On Thu, Jun 13, 2019 at 11:38:38AM -0700, Nathan Huckleberry wrote:
> Hey all,
> 
> I'm looking into cleaning up ignored warnings in the kernel so we can
> remove compiler flags to ignore warnings.
> 
> There's an unused variable ('mbox_cmd_name') in xhci-tegra.c. Looks
> like it was intended for logging or debugging, but never used. Just
> wanted to reach out to ask the best steps for cleaning this up.
> 
> If the variable is no longer needed I'd like to send a patch to remove it.
> 
> https://github.com/ClangBuiltLinux/linux/issues/533

Feel free to send that patch. If we ever need this debug information
again we can easily add it back by reverting.

Thierry

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