Re: why does the lcd display so lag.

Archer <xydarcher@xxxxxxx> wrote:
Hans-Bernhard Broeker wrote:
Archer <xydarcher@xxxxxxx> wrote:

we are using H7202 an Arm7 chip(70MHz) to run linux. When we
use X with LCD whose resolution is 640*480 and 8 bit depth, it is
too lag to run smoothly.

Which "it" is that: the CPU, the X server, or the LCD? And how
sluggish is it, actually?

It means the picture of display. The picture appeared very slow. It
will twinkle when we change some text content dynamicly.

[Please don't top-post. Fixed.]

So basically, it means you have no idea where the bottleneck is.
You only know that by the time the contents arrive on the screen,
they're too late.

But how on earth could "to twinkle" apply to an LCD screen? I don't
think that term has any recognized meaning other than those applied to
stars in the sky, and maybe to jewels.

Anyway, text output may not be the best test case here. Text output
over a graphical display pipeline like X11 involves considerable work,
which often has to be done by software. Try whooshing a small
graphical object (a short line, maybe even a single dot) around,
instead.

What kind of LCD controller do you use? Does it have any kind of
hardware support for drawing of 2D graphics primitives? If so, is
there a proper X server for it, or are you relying on the framebuffer
server?

--
Hans-Bernhard Broeker (broeker@xxxxxxxxxxxxxxxxxxxxx)
Even if all the snow were burnt, ashes would remain.
.

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