diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2015-01-19 08:44:07 +0100 |
|---|---|---|
| committer | Hans de Goede <hdegoede@redhat.com> | 2015-01-22 12:34:56 +0100 |
| commit | 7cd6f92d41a4bb364eb223f216334c0676eb7e97 (patch) | |
| tree | 2354c87785d555f8d458b0f3956a0fb20211b84d /arch/arm/include/asm/arch-sunxi/clock_sun4i.h | |
| parent | 1cf054a8839ee6f096a0cb5d40640efdec235b2b (diff) | |
sunxi: video: Use frontend for dma on sun4i to fix memory bandwidth problems
Testing has shown that on sun4i the display backend engine does not have
deep enough fifo-s causing flickering / tearing in full-hd mode due to
fifo underruns. On sun4i use the display frontend engine to do the dma from
memory, as the frontend does have deep enough fifo-s.
As added advantage of this is that it results in much better memory bandwidth
as it reduces the amount of dram bank switches, for more details see:
http://ssvb.github.io/2014/11/11/revisiting-fullhd-x11-desktop-performance-of-the-allwinner-a10.html
Note that this changes the pipeline searched for in the simplefb node, we can
get away with doing this now, since no kernel has yet shipped with simplefb
dtb nodes, and I will make sure to get a simplefb node with the new pipeline
into 3.19 before it ships.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Diffstat (limited to 'arch/arm/include/asm/arch-sunxi/clock_sun4i.h')
| -rw-r--r-- | arch/arm/include/asm/arch-sunxi/clock_sun4i.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arch-sunxi/clock_sun4i.h b/arch/arm/include/asm/arch-sunxi/clock_sun4i.h index 5ebf8564d4..05fbad3e11 100644 --- a/arch/arm/include/asm/arch-sunxi/clock_sun4i.h +++ b/arch/arm/include/asm/arch-sunxi/clock_sun4i.h @@ -186,6 +186,7 @@ struct sunxi_ccm_reg { /* ahb clock gate bit offset (second register) */ #define AHB_GATE_OFFSET_GMAC 17 +#define AHB_GATE_OFFSET_DE_FE0 14 #define AHB_GATE_OFFSET_DE_BE0 12 #define AHB_GATE_OFFSET_HDMI 11 #define AHB_GATE_OFFSET_LCD1 5 @@ -266,7 +267,10 @@ struct sunxi_ccm_reg { #define CCM_MMC_CTRL_PLL5 (0x2 << 24) #define CCM_MMC_CTRL_ENABLE (0x1 << 31) +#define CCM_DRAM_GATE_OFFSET_DE_FE1 24 /* Note the order of FE1 and */ +#define CCM_DRAM_GATE_OFFSET_DE_FE0 25 /* FE0 is swapped ! */ #define CCM_DRAM_GATE_OFFSET_DE_BE0 26 +#define CCM_DRAM_GATE_OFFSET_DE_BE1 27 #define CCM_LCD_CH0_CTRL_PLL3 (0 << 24) #define CCM_LCD_CH0_CTRL_PLL7 (1 << 24) |