On Sat, Aug 25, 2018 at 03:54:17PM -0400, Mikulas Patocka wrote:
> This is a simple optimization for fifo waiting that improves scrolling
> performance by 5%. If the queue has more free entries that what we
> consume, we can skip the costly register read next time.
>
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
>
> ---
> drivers/video/fbdev/aty/atyfb.h | 12 ++++++++----
> drivers/video/fbdev/aty/mach64_accel.c | 4 +++-
> 2 files changed, 11 insertions(+), 5 deletions(-)
>
> Index: linux-stable/drivers/video/fbdev/aty/atyfb.h
> ===================================================================
> --- linux-stable.orig/drivers/video/fbdev/aty/atyfb.h 2018-08-25 21:49:16.000000000 +0200
> +++ linux-stable/drivers/video/fbdev/aty/atyfb.h 2018-08-25 21:52:51.000000000 +0200
> @@ -147,6 +147,7 @@ struct atyfb_par {
> u16 pci_id;
> u32 accel_flags;
> int blitter_may_be_busy;
> + unsigned fifo_space;
> int asleep;
> int lock_blank;
> unsigned long res_start;
> @@ -346,10 +347,13 @@ extern int aty_init_cursor(struct fb_inf
> * Hardware acceleration
> */
>
> -static inline void wait_for_fifo(u16 entries, const struct atyfb_par *par)
> +static inline void wait_for_fifo(u16 entries, struct atyfb_par *par)
> {
> - while ((aty_ld_le32(FIFO_STAT, par) & 0xffff) >
> - ((u32) (0x8000 >> entries)));
> + unsigned fifo_space = par->fifo_space;
> + while (entries > fifo_space) {
> + fifo_space = 16 - fls(aty_ld_le32(FIFO_STAT, par) & 0xffff);
I don't recall off hand which way this register works, but based
on the existing code this looks correct.
Reviewed-by: Ville Syrjälä <syrjala@xxxxxx>
> + }
> + par->fifo_space = fifo_space - entries;
> }
>
> static inline void wait_for_idle(struct atyfb_par *par)
> @@ -359,7 +363,7 @@ static inline void wait_for_idle(struct
> par->blitter_may_be_busy = 0;
> }
>
> -extern void aty_reset_engine(const struct atyfb_par *par);
> +extern void aty_reset_engine(struct atyfb_par *par);
> extern void aty_init_engine(struct atyfb_par *par, struct fb_info *info);
>
> void atyfb_copyarea(struct fb_info *info, const struct fb_copyarea *area);
> Index: linux-stable/drivers/video/fbdev/aty/mach64_accel.c
> ===================================================================
> --- linux-stable.orig/drivers/video/fbdev/aty/mach64_accel.c 2018-08-25 21:49:16.000000000 +0200
> +++ linux-stable/drivers/video/fbdev/aty/mach64_accel.c 2018-08-25 21:49:16.000000000 +0200
> @@ -37,7 +37,7 @@ static u32 rotation24bpp(u32 dx, u32 dir
> return ((rotation << 8) | DST_24_ROTATION_ENABLE);
> }
>
> -void aty_reset_engine(const struct atyfb_par *par)
> +void aty_reset_engine(struct atyfb_par *par)
> {
> /* reset engine */
> aty_st_le32(GEN_TEST_CNTL,
> @@ -50,6 +50,8 @@ void aty_reset_engine(const struct atyfb
> /* HOST errors */
> aty_st_le32(BUS_CNTL,
> aty_ld_le32(BUS_CNTL, par) | BUS_HOST_ERR_ACK | BUS_FIFO_ERR_ACK, par);
> +
> + par->fifo_space = 0;
> }
>
> static void reset_GTC_3D_engine(const struct atyfb_par *par)
--
Ville Syrjälä
syrjala@xxxxxx
http://www.sci.fi/~syrjala/
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