2021-09-20 15:40:29

by Arnd Bergmann

Subject: [PATCH] drm/amd/display: fix empty debug macros

From: Arnd Bergmann <[email protected]>

Using an empty macro expansion as a conditional expression
produces a W=1 warning:

drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c: In function 'dce_aux_transfer_with_retries':
drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c:775:156: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
775 | "dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_DEFER");
| ^
drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c:783:155: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
783 | "dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK");
| ^

Expand it to "do { } while (0)" instead to make the expression
more robust and avoid the warning.

Fixes: 56aca2309301 ("drm/amd/display: Add AUX I2C tracing.")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
index e14f99b4b0c3..3c3347341103 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
@@ -42,7 +42,7 @@
#define DC_LOGGER \
engine->ctx->logger

-#define DC_TRACE_LEVEL_MESSAGE(...) /* do nothing */
+#define DC_TRACE_LEVEL_MESSAGE(...) do { } while (0)
#define IS_DC_I2CAUX_LOGGING_ENABLED() (false)
#define LOG_FLAG_Error_I2cAux LOG_ERROR
#define LOG_FLAG_I2cAux_DceAux LOG_I2C_AUX
@@ -76,7 +76,7 @@ enum {
#define DEFAULT_AUX_ENGINE_MULT 0
#define DEFAULT_AUX_ENGINE_LENGTH 69

-#define DC_TRACE_LEVEL_MESSAGE(...) /* do nothing */
+#define DC_TRACE_LEVEL_MESSAGE(...) do { } while (0)

static void release_engine(
struct dce_aux *engine)
--
2.29.2

2021-09-21 01:36:31

by Alex Deucher

Subject: Re: [PATCH] drm/amd/display: fix empty debug macros

On Mon, Sep 20, 2021 at 8:16 AM Arnd Bergmann <[email protected]> wrote:
>
> From: Arnd Bergmann <[email protected]>
>
> Using an empty macro expansion as a conditional expression
> produces a W=1 warning:
>
> drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c: In function 'dce_aux_transfer_with_retries':
> drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c:775:156: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
> 775 | "dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_DEFER");
> | ^
> drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c:783:155: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
> 783 | "dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK");
> | ^
>
> Expand it to "do { } while (0)" instead to make the expression
> more robust and avoid the warning.
>
> Fixes: 56aca2309301 ("drm/amd/display: Add AUX I2C tracing.")
> Signed-off-by: Arnd Bergmann <[email protected]>

Applied. Thanks!

Alex

> ---
> drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> index e14f99b4b0c3..3c3347341103 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> @@ -42,7 +42,7 @@
> #define DC_LOGGER \
> engine->ctx->logger
>
> -#define DC_TRACE_LEVEL_MESSAGE(...) /* do nothing */
> +#define DC_TRACE_LEVEL_MESSAGE(...) do { } while (0)
> #define IS_DC_I2CAUX_LOGGING_ENABLED() (false)
> #define LOG_FLAG_Error_I2cAux LOG_ERROR
> #define LOG_FLAG_I2cAux_DceAux LOG_I2C_AUX
> @@ -76,7 +76,7 @@ enum {
> #define DEFAULT_AUX_ENGINE_MULT 0
> #define DEFAULT_AUX_ENGINE_LENGTH 69
>
> -#define DC_TRACE_LEVEL_MESSAGE(...) /* do nothing */
> +#define DC_TRACE_LEVEL_MESSAGE(...) do { } while (0)
>
> static void release_engine(
> struct dce_aux *engine)
> --
> 2.29.2
>