##3 Frame Buffer Questions?

Hi Folks,

 

I have a question.


Working on a "semi-custom" frame buffer for a Xilinx FPGA with the
Microblaze.

 

The specific file we started with is already in the
uclinux/drivers/video and is called xilinxfb.c

 

We can register the driver and a debug trace in the driver shows that it
registers as FB0 29-0, so that should be right.

 

However, if I do a cat /dev/fb0  the linux responds by saying it can't
open the device. It appears that somehow the default file pointer in
dev/fb0 cannot connect to the actual driver?

 

MKNODing the driver also fails.

 

I do have other drivers that we have made that do install, so this isn't
the first attempt at a driver.

 

Any thoughts on where I may look for some ideas on this?

 

Thanks!

 

Steve Spano, President

Finger Lakes Engineering

119 South Cayuga #200

Ithaca, Ny 14850

(V) 607-277-1614 x223

(C) 607-342-1150

www.FL-ENG.com - FLE's Main Website

www.FLEDEVFORUM.com - FLE's Developer Forum

 

 

On Fri, 2006-08-18 at 10:30 -0400, Steve Spano wrote:

Hi Folks,

 

I have a question.


Working on a “semi-custom” frame buffer for a Xilinx FPGA with the
Microblaze.

 

The specific file we started with is already in the
uclinux/drivers/video and is called xilinxfb.c

 

We can register the driver and a debug trace in the driver shows that
it registers as FB0 29-0, so that should be right.

 

However, if I do a cat /dev/fb0  the linux responds by saying it can’t
open the device. It appears that somehow the default file pointer in
dev/fb0 cannot connect to the actual driver?

 

MKNODing the driver also fails.

 

I do have other drivers that we have made that do install, so this
isn’t the first attempt at a driver.

 

Any thoughts on where I may look for some ideas on this?

What kernel version are you using?
Does it show up in /proc/fb? If it does, the device node it's bound too
should also show up.

If it does show up in /proc/fb, then make sure that info->screen_base
(in 2.6) or info->disp->screen_base (in 2.4) is pointing to the virtual
address of the framebuffer.

If publicly available, can you point us to the source?

Tony




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Hi Antonino,

We got the buffer working and showing now in the proc folder

So we can now do a cat random > fb0 - and that works.

Do you (or someone) know the correct pattern of magic #defines that will
put the console up on the VGA? I would like to see the startup
messages/login prompt on the VGA display.

Thanks!

Steve Spano, President
Finger Lakes Engineering
119 South Cayuga #200
Ithaca, Ny 14850
(V) 607-277-1614 x223
(C) 607-342-1150
www.FL-ENG.com - FLE's Main Website 
www.FLEDEVFORUM.com - FLE's Developer Forum

-----Original Message-----
From: Antonino A. Daplas [mailto:adaplas@gmail.com] 
Sent: Friday, August 18, 2006 8:20 PM
To: steve@flconsult.com; linux-fbdev-devel@lists.sourceforge.net
Subject: Re: [Linux-fbdev-devel] ##3 Frame Buffer Questions?

On Fri, 2006-08-18 at 10:30 -0400, Steve Spano wrote:

Hi Folks,

 

I have a question.


Working on a "semi-custom" frame buffer for a Xilinx FPGA with the
Microblaze.

 

The specific file we started with is already in the
uclinux/drivers/video and is called xilinxfb.c

 

We can register the driver and a debug trace in the driver shows that
it registers as FB0 29-0, so that should be right.

 

However, if I do a cat /dev/fb0  the linux responds by saying it can't
open the device. It appears that somehow the default file pointer in
dev/fb0 cannot connect to the actual driver?

 

MKNODing the driver also fails.

 

I do have other drivers that we have made that do install, so this
isn't the first attempt at a driver.

 

Any thoughts on where I may look for some ideas on this?

What kernel version are you using?
Does it show up in /proc/fb? If it does, the device node it's bound too
should also show up.

If it does show up in /proc/fb, then make sure that info->screen_base
(in 2.6) or info->disp->screen_base (in 2.4) is pointing to the virtual
address of the framebuffer.

If publicly available, can you point us to the source?

Tony








-------------------------------------------------------------------------
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Get stuff done quickly with pre-integrated technology to make your job easier
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http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

On Fri, 2006-08-18 at 22:43 -0400, Steve Spano wrote:

Hi Antonino,

We got the buffer working and showing now in the proc folder

So we can now do a cat random > fb0 - and that works.

Do you (or someone) know the correct pattern of magic #defines that will
put the console up on the VGA? I would like to see the startup
messages/login prompt on the VGA display.

CONFIG_VT=y;
CONFIG_FRAMEBUFFER=m or y (of course)
CONFIG_FRAMEBUFFER_CONSOLE=y (or CONFIG_FRAMEBUFFER_CONSOLE=m followed
by modprobe fbcon)
CONFIG_FONT_8x16 (or any built-in fonts available).

In your boot parameters, include console=tty0, just to be sure.

Tony



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Hi There

Thanks again for the help - very much appreciated.

Still not seeing the terminal on the display.

We have linux running in a FPGA. The FPGA has a vga-ish hardware core
inside of it. The core transfers 16/32bit pixels from the frame buffer
to the display.

It looked like there were options for a display that had a built in
character generator and there were options for the "VGA console"

Do you (or someone) have an autoconf.h that you could share for a linux
build that properly displays the bash/logins/startup on a VGA display?

Thanks so much!

Steve Spano, President
Finger Lakes Engineering
119 South Cayuga #200
Ithaca, Ny 14850
(V) 607-277-1614 x223
(C) 607-342-1150
www.FL-ENG.com - FLE's Main Website 
www.FLEDEVFORUM.com - FLE's Developer Forum

-----Original Message-----
From: Antonino A. Daplas [mailto:adaplas@gmail.com] 
Sent: Saturday, August 19, 2006 5:45 AM
To: steve@flconsult.com; linux-fbdev-devel@lists.sourceforge.net
Subject: Re: [Linux-fbdev-devel] ##3 Frame Buffer Questions?

On Fri, 2006-08-18 at 22:43 -0400, Steve Spano wrote:

Hi Antonino,

We got the buffer working and showing now in the proc folder

So we can now do a cat random > fb0 - and that works.

Do you (or someone) know the correct pattern of magic #defines that

will

put the console up on the VGA? I would like to see the startup
messages/login prompt on the VGA display.

CONFIG_VT=y;
CONFIG_FRAMEBUFFER=m or y (of course)
CONFIG_FRAMEBUFFER_CONSOLE=y (or CONFIG_FRAMEBUFFER_CONSOLE=m followed
by modprobe fbcon)
CONFIG_FONT_8x16 (or any built-in fonts available).

In your boot parameters, include console=tty0, just to be sure.

Tony







-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642