Re: [Linux-fbdev-devel] [PATCH] Disable mach64 accelerator if stride is not multiple of 64

[Ville S. <sy...@sc...>]

On Wed, Jun 17, 2009 at 05:05:31PM -0400, Mikulas Patocka wrote:
> On Wed, 17 Jun 2009, Ville Syrjälä wrote:
> 
> > I was under the impression that 64 byte aligned offset and pitch are only
> > required if block writes are used. But perhaps it is always required
> > with SGRAM/WRAM, or perhaps you have auto block writes enabled. Can you
> > check the memory type and the the value of the HW_DEBUG register?
> 
> Memory is SGRAM M32L1632512A-8Q. See this: 
> http://www.digchip.com/datasheets/parts/datasheet/581/M32L1632512A.php
> 
> The status line is:
> atyfb: 3D RAGE PRO (Mach64 GP, PQFP, PCI) [0x4750 rev 0x7c]
> atyfb: 4M SGRAM (1:1), 14.31818 MHz XTAL, 230 MHz PLL, 100 Mhz MCLK, 100 
> MHz XCLK
> 
> The debug register is zero (printed with printk("ATI INIT ENGINE, DEBUG 
> %08X", aty_ld_le32(HW_DEBUG, par)); at the end of aty_init_engine).

OK then it has auto block writes enabled.

> > > This patch disables accelerator if scanline is not multiple of 64 bytes.
> > 
> > A better option would be to round the pitch up in check_var(). Also it
> > would be more proper to use fix.line_length as the pitch value instead
> > of var.xres_virtual. That way check_var() could leave var.xres_virtual
> > alone and just round fix.line_length to whatever is required.
> > 
> > Actually now that I think about it I would prefer to round to 64 bytes
> > always when SGRAM/WRAM is found. The reason is that the mach64 DirectFB
> > driver always enables auto block writes on SGRAM boards and if atyfb
> > uses less alignment things will not work correctly. Perhaps atyfb should
> > enable auto block writes too.
> 
> So patch it to align line length (I don't know fb well to pick the right 
> place) and send me the patch and I'll test it.

I cooked up a patch and briefly tested it on my Dell Inspiron 7000
which has an LT Pro /w SGRAM. I will send it as part of a series now.

-- 
Ville Syrjälä
sy...@sc...
http://www.sci.fi/~syrjala/