On 08/27/2018 02:55 PM, Ville Syrj채l채 wrote:
On Sat, Aug 25, 2018 at 03:54:17PM -0400, Mikulas Patocka wrote:
quoted
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@redhat.com>
---
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 Syrj채l채 <syrjala@sci.fi>
Patch queued for 4.20, thanks.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics