nanogui: Shaky display
Subject:
Re: [nanogui] Shaky display
From:
Misbahullah Khan ####@####.####
Date:
13 Jun 2008 09:53:52 -0000
Message-Id: <OF7174879D.14739BDA-ON65257467.003628F1-65257467.00366E73@lntemsys.com>
Hi Greg ,
Even if i am accesseing the data RAM asynchronously there should not be
any flickering at the display
this is what the data sheet ( SPLC501C )says. Hence i assume that even i
do access asynchronously
the controller should refresh and hence flickering should never happen at
the display.
>This looks like an interlaced scan issue or something like that...
>when the screen is not physically refreshing?
Screen should be refreshed by the controller always. when do you think
that the
screen should not be refreshing??
Even if the data is written wrong due to inappropiate timing while
writing, the screen should be refreshed at the next time and the user the
should never see the data getting corrupted on the display.
Could you please explain me how interlaced issue is related which you have
mentioned earlier ????
Thanks & Regards,
Misbah
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KIADB indusrial area, Hebbal,Hootagalli.
Mysore,
India 570018
Phone: 08212405398 Extn: 5172
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"Greg Haerr" ####@####.####
06/12/2008 09:17 PM
Please respond to
"Greg Haerr" ####@####.####
To
"Misbahullah Khan" ####@####.####
cc
####@####.#### ####@####.#### "Sanjeev GT"
####@####.####
Subject
Re: [nanogui] Shaky display
This looks like an interlaced scan issue or something like that...
Could it be you need to draw the screen memory only during certain
times, e.g. when the screen is not physically refreshing?
Perhaps you need to wait for a vertical sync?
Regards,
Greg
----- Original Message -----
From: Misbahullah Khan
To: Greg Haerr
Cc: ####@####.#### ; ####@####.#### ; Sanjeev GT
Sent: Wednesday, June 11, 2008 6:33 AM
Subject: Re: [nanogui] Shaky display
Hi Greg ,
To give you a better idea of the exact display issue, i am enclosing the
snapshot of the display.
>I assume
>you are running a straight framebuffer driver. If not,
>then there are additional drawing issues.
We have not enabled the framebuffer driver in the kernel.The screen
driver in the
microwindow directly calls the lcd driver and also we are statically
building the
nano-X lib.
As you have mentioned there could be some other drawing issue we would
like to
know that.
Thanks & Regards,
Misbah
_____________________________________
EmSyS Division,
Larsen & Toubro Limited,
KIADB indusrial area, Hebbal,Hootagalli.
Mysore,
India 570018
Phone: 08212405398 Extn: 5172
_____________________________________
This mail is classified as :
( ) L&T EmSyS Proprietary
( ) L&T EmSyS Confidential
( ) L&T EmSyS Internal Use
( ) L&T EmSyS General Business
"Greg Haerr" ####@####.####
06/11/2008 05:03 AM Please respond to
"Greg Haerr" ####@####.####
To "Misbahullah Khan" ####@####.####
cc ####@####.####
Subject Re: [nanogui] Shaky display
: 1. It happens to be sometimes (1 in 20-30 times) that whenever i try
to
: wtite a text to lcd display or fill a bar the text is written
horizontaly
: about some percentage (say 50 %) and then again writes the same text
the
: remaining percentage makeing the display as if one text is written
twice
: half and half one over the other .
:
: Similarly when we are dispalying the a horizontal bar the bar gers
: displayed two times one over the other horizontaly.
I'm still confused as to whether you're describing a hardware
jitter or suggesting that perhaps the software is drawing
multiple times to appear "jittery." I don't think there
are any known bugs regarding the latter. I assume
you are running a straight framebuffer driver. If not,
then there are additional drawing issues.
: Is there any thing we could see into the microwindow ???
:
: Please do share your experience and knowledge regarding this concern .
Carlo's response regarding the OS framebuffer driver sounds
like something that can definitely be related to visual strangeness.
Notice this also applies to a system where there isn't really
a memory-mapped framebuffer, but some other mechanism
for drawing.
Regards,
Greg
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