[loongson-dev] mclk & m1xclk of sm502

[yajin]

Hi all,

The mclx and m2xclk in sm501.c of linux mainline is 72&144MHZ. But these two clocks in gdium are 84&112MHZ. If I use the linux default value 72&144MHZ, then the LCD display has a little problem. My question is that why these two values in gdium are 84&122MHZ? Can gdium work under other clock freq, like 72&144MHZ?


yajin

http://vm-kernel.org

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[Yanhua]

teddy, 
   Could you please explain it?

2010/4/27 yajin <yaji...@vm-kernel.org>

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[zhangfx]

On 2010年04月27日 12:59, yajin wrote:
> Hi all,
>
> The mclx and m2xclk in sm501.c of linux mainline is 72&144MHZ. But
> these two clocks in gdium are 84&112MHZ. If I use the linux default
> value 72&144MHZ, then the LCD display has a little problem. My
> question is that why these two values in gdium are 84&122MHZ? Can
> gdium work under other clock freq, like 72&144MHZ?

Due to different video ram chip and PCB layout, 502 can have different
max clock. E.g. Lemote Lynloong should be able to work at 157MHz.

[yajin]

>Due to different video ram chip and PCB layout, 502 can have different max clock. E.g. Lemote Lynloong should be able to work at 157MHz.

So that means the clocks should be set to different value according to different machine?

yajin

http://vm-kernel.org

2010/4/28 zhangfx <zha...@lemote.com>

[zhangfx]

On 2010年04月28日 18:39, yajin wrote:

>Due to different video ram chip and PCB layout, 502 can have different max clock. E.g. Lemote Lynloong should be able to work at 157MHz.

So that means the clocks should be set to different value according to different machine?

Yes, might diff for different model. But there are some values most models should support. Higher clock means higher performance(since the video data can be moved more quickly) and (slightly) more power comsumption.