Subject:
Re: [nanogui] Flicker with dynamic images
From:
"Robert S. Grimes" ####@####.####
Date:
13 Apr 2009 14:51:28 -0000
Message-Id: <49E35162.7000404@rcn.com>
Hi Ricardo,
Ricardo Jasinski wrote:
> Hi Robert,
>
> I believe the first thing to do would be switching to the latest CVS
> version from the repository. Many have found issues with the
> touchscreen library, and quite a few have been resolved from what I've
> seen recently on this list.
>
I had switched from CVS to the Freescale version because the former's
kernel doesn't support 320 (x) x 240 (h) LCD screen layout. Not sure
what to do about this...
> Secondly, could you easily run some tests using a higher frequency
> system clock? The fact that the artifacts appear at the bottom of the
> screen might suggest that the screen is not being updated as often as
> it should be. Alternatively, you could slow your system down and see
> if things gets worse.
>
I'm not sure about how to do this, but I'll give it a shot. I'll only
be able to run slower, though - but if that makes things worse, that'll
be useful!
> Third, you could try running the other demos, which might give us new
> insights into these issues - perhaps they are related to cpu usage,
> somehow?
>
Okay, I'll give them a shot. As I'm not sure what they are supposed to
do, it's difficult to know how their performance agrees or differs from
what they should be doing! It's also difficult to describe how they
fail (and by the way, they all do fail, as far as I can tell). But I'll
try to describe things as well as I can.
I won't be able to get to this until tomorrow, though, so I'm still open
to other ideas...
Thanks,
-Bob
> Good luck,
>
> Ricardo.
>
>
> 2009/4/12 Robert S. Grimes ####@####.####
>
>> Hi,
>>
>> I'm working with a board derived from the Freescale/LogicPD mcf5329
>> evaluation board, and using the microwindows-0.90 package which is
>> included in ltib-cf_nommu-20081215 from Freescale's web site. The
>> framebuffer (kernel is linux-2.6.26) is set up for a 320 wide by 240
>> high LCD. The penguin shows fine on power-up.
>>
>> But, when I try to run some of the demo apps, I get mixed results at
>> best. As a good example of exactly where I'm at, if I
>> run /usr/nanox/launcher.sh, I get what appears to be a 3 x 3 matrix of
>> icons, presumably for launching other demo apps; the icons included are
>> (top row) Tetrix, Slider, Terminal; (middle row) Clock, Magnifier,
>> Scribble, (bottom row) Roach, Tux, and NXEyes. This matrix has its
>> lower left corner aligned with the lower left corner of the screen, and
>> does not occupy the entire screen; the remainder (about the top 25% and
>> the rightmost 10%) seems to be some patterned background. All this
>> appears good - I say "appears" as I'm not really sure what to expect.
>> However, there is a big problem - the bottom ~20% of the screen has a
>> flicker that exhibits itself as random row-wide artifacts. What I mean
>> is that it seems some rows really are not being drawn - for example, row
>> 200 might be drawn, row 201 gets skipped, and row 202 gets drawn where
>> 201 should be. I say this because it appears that the labels of the
>> bottom three icons (i.e. Roach, Tux, and NXEyes jump up and down a row
>> or two. The rest of the display is rock-solid.
>>
>> After playing with this a while, I've discovered something. After about
>> 15 seconds, the launcher.sh demo goes into a random screensaver mode.
>> Some screensavers look really good, such as a "searchlight" that
>> illuminates a small circle that is moved over the display, the rest of
>> which is black - simulating a flashlight searching in a darkened room.
>> For this screensaver, every thing is sharp, and there is no flicker
>> whatsoever. Other screensavers, such as one that looks like lighting
>> flashes, exhibits the flicker over large portions of the display - not
>> just the bottom portion.
>>
>> Other screensavers show either extreme, or behavior in between them.
>> What seems to be going on is that the more dynamic the graphics, the
>> more the flicker is exhibited. Put another way, the more static the
>> display, the less flicker is noticed. I would expect that a totally
>> static display might well show no flicker whatsoever. (Note: I don't
>> know if the launcher.sh main screen is indeed fully static - it would
>> appear to be, but perhaps something at the very bottom isn't).
>>
>> This would seem to be timing related or something, but I haven't been
>> able to find anything amiss in the stock code. I did come across
>> something regarding priority of the LCD controller on the internal
>> crossbar switch, but it appears that it has already been elevated to the
>> highest priority by the kernel.
>>
>> I'm completely stumped by this - anyone have any ideas on what might be
>> amiss, or what to investigate?
>>
>> Thanks,
>> -Bob
>>
>>
>>
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