* [PATCH] backlight: s6e63m0: make const arrays static, reduces object code size
@ 2017-09-12 11:45 Colin King
2017-09-12 13:12 ` Daniel Thompson
0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2017-09-12 11:45 UTC (permalink / raw)
To: Lee Jones, Daniel Thompson, Jingoo Han, Bartlomiej Zolnierkiewicz,
linux-fbdev
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Don't populate const arrays on the stack, instead make them
static. Makes the object code smaller by nearly 400 bytes:
Before:
text data bss dec hex filename
15164 6336 0 21500 53fc drivers/video/backlight/s6e63m0.o
After:
text data bss dec hex filename
14669 6432 0 21101 526d drivers/video/backlight/s6e63m0.o
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/video/backlight/s6e63m0.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/backlight/s6e63m0.c b/drivers/video/backlight/s6e63m0.c
index 3c4a22a3063a..965c660b2f6b 100644
--- a/drivers/video/backlight/s6e63m0.c
+++ b/drivers/video/backlight/s6e63m0.c
@@ -446,7 +446,7 @@ static int s6e63m0_gamma_ctl(struct s6e63m0 *lcd, int gamma)
static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
{
int ret, i;
- const unsigned short *init_seq[] = {
+ static const unsigned short *init_seq[] = {
seq_panel_condition_set,
seq_display_condition_set,
seq_gamma_setting,
@@ -467,7 +467,7 @@ static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
static int s6e63m0_ldi_enable(struct s6e63m0 *lcd)
{
int ret = 0, i;
- const unsigned short *enable_seq[] = {
+ static const unsigned short *enable_seq[] = {
seq_stand_by_off,
seq_display_on,
};
--
2.14.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] backlight: s6e63m0: make const arrays static, reduces object code size
2017-09-12 11:45 [PATCH] backlight: s6e63m0: make const arrays static, reduces object code size Colin King
@ 2017-09-12 13:12 ` Daniel Thompson
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Thompson @ 2017-09-12 13:12 UTC (permalink / raw)
To: Colin King, Lee Jones, Jingoo Han, Bartlomiej Zolnierkiewicz,
linux-fbdev
Cc: kernel-janitors, linux-kernel
On 12/09/17 12:45, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Don't populate const arrays on the stack, instead make them
> static. Makes the object code smaller by nearly 400 bytes:
>
> Before:
> text data bss dec hex filename
> 15164 6336 0 21500 53fc drivers/video/backlight/s6e63m0.o
>
> After:
> text data bss dec hex filename
> 14669 6432 0 21101 526d drivers/video/backlight/s6e63m0.o
For future records, can you record the compiler version, architecture
and optimization level (-O2 or -Os) to the patch header?
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/video/backlight/s6e63m0.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/s6e63m0.c b/drivers/video/backlight/s6e63m0.c
> index 3c4a22a3063a..965c660b2f6b 100644
> --- a/drivers/video/backlight/s6e63m0.c
> +++ b/drivers/video/backlight/s6e63m0.c
> @@ -446,7 +446,7 @@ static int s6e63m0_gamma_ctl(struct s6e63m0 *lcd, int gamma)
> static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
> {
> int ret, i;
> - const unsigned short *init_seq[] = {
> + static const unsigned short *init_seq[] = {
I'd be inclined to throw in an extra const to help the compile spot any
negligent maintenance in the future:
static const unsigned short * const init_seq[];
> seq_panel_condition_set,
> seq_display_condition_set,
> seq_gamma_setting,
> @@ -467,7 +467,7 @@ static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
> static int s6e63m0_ldi_enable(struct s6e63m0 *lcd)
> {
> int ret = 0, i;
> - const unsigned short *enable_seq[] = {
> + static const unsigned short *enable_seq[] = {
> seq_stand_by_off,
> seq_display_on,
> };
>
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