[PATCH 1/2] drm: Only #define DEBUG if CONFIG_DYNAMIC_DEBUG is disabled
Zhang, Jerry(Junwei)
Jerry.Zhang at amd.com
Thu Dec 6 02:40:42 UTC 2018
On 12/6/18 12:56 AM, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer at amd.com>
>
> The following cases are possible for pr_debug():
>
> 1. CONFIG_DYNAMIC_DEBUG disabled
> a) DEBUG not defined: pr_debug() translates to no_printk(...), i.e.
> it never generates any output.
> b) DEBUG defined: pr_debug() translates to printk(KERN_DEBUG ...),
> i.e. it generates output which doesn't appear in dmesg by default,
> can be enabled dynamically.
>
> 2. CONFIG_DYNAMIC_DEBUG enabled: pr_debug() translates to
> dynamic_pr_debug()
> a) DEBUG not defined: dynamic_pr_debug() generates no output by
> default, can be enabled dynamically.
> b) DEBUG defined: dynamic_pr_debug() generates output by default,
> can be disabled dynamically.
>
> The intention for drm_debug_printer() is to generate output which
> doesn't appear in dmesg by default, but can be enabled dynamically, i.e.
> cases 1b) and 2a). However, defining DEBUG unconditionally gave us 2b)
> instead of 2a) with CONFIG_DYNAMIC_DEBUG enabled.
>
> Fixes: 79a5ad2fdb3c ("drm: Enable pr_debug() for drm_printer")
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang at amd.com>
> ---
> drivers/gpu/drm/drm_print.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index 0e7fc3e7dfb4..ee56e4a1b343 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -23,11 +23,13 @@
> * Rob Clark <robdclark at gmail.com>
> */
>
> -#define DEBUG /* for pr_debug() */
> -
> #include <stdarg.h>
> #include <linux/seq_file.h>
> #include <drm/drmP.h>
> +
> +#ifndef CONFIG_DYNAMIC_DEBUG
> +#define DEBUG /* for pr_debug() */
> +#endif
> #include <drm/drm_print.h>
>
> void __drm_puts_coredump(struct drm_printer *p, const char *str)
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