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Re: nvidiafb problems



On Sun, 2008-06-29 at 09:22 -0700, Les wrote:
> Hi, Russel,
> 	Segfaults are probably your best indication of the problem.
> Generically a segmentation fault occurs when you access memory allocated
> to another process.  You can tramp all over your own processes memory
> and not necessarily generate a segfault.  Since you are seeing the
> problem when the size of the field changes, probably there is a fixed
> array somewhere in your code that is inappropriately sized for the
> larger screen sizes.  Also, if the Video processor is only sensing 64M,
> it may be doing something weird as well.  
> 
> 	To trouble shoot this problem I would probably first check the video
> processor to make sure it is properly seated in its socket.  Next I
> would go carefully through the code looking for hard sized arrays or
> fixed malloc sizes.  Check the #defines carefully to see what they have
> and what comments you may have added about display sizes.  Then look at
> any pointer use to make sure that it is cordoned off from exceeding the
> array sizes in use.
> 
> After that you will need some software to monitor memory.  Several forms
> exist, and I haven't used any in years, so I cannot recommend one for
> you.  But if you check the archives, you will find some references last
> year if I remember correctly.
> 
> 	Also because Nvidia is proprietary, the group here has no vision into
> their code or processes.  And if your code is producing segfaults, that
> needs to be cleaned up before submitting bug reports anyway.
> 
> REgards,
> Les H
> On Sat, 2008-06-28 at 17:48 -0700, Russell Miller wrote:
> > I have been having this problem for a while.  I was told on the fedora
> > IRC channel that "this has nothing to do with fedora" and to stop my
> > blathering, but I think that it is something that perhaps the
> > community should at least be aware of and perhaps even hopefully can
> > help me to solve.
> > 
> > I am having an odd problem with nvidiafb.  I have written a program to
> > do a mandelbrot set over framebuffer, just to learn how to make
> > mandelbrot sets and how to use the framebuffer.  The program worked
> > fine on some old hardware I had - an older nvidia AGP card.  But after
> > I upgraded to a 6200, along with a Dual-core X2-based motherboard,
> > suddenly it stops working.  More accurately, the framebuffer works
> > fine at 1280x1024 until I start the program, at which time the image
> > moves rapidly across the screen, reminiscent of an old TV that has
> > lost its horizontal sync.  This does not happen at 640x480, and going
> > up in resolution the side-to-side motion gets progressively faster.
> > 
> > Obviously, this is useless for my purposes.
> > 
> > I worked with the directfb people to try to rule out directfb being
> > the culprit.  After I managed to get this working under VESA (with no
> > acceleration, obviously, so it's almost useless), that pretty much
> > ruled out directfb being the problem.  So I'm having to think that for
> > some reason the nvidiafb driver is just not playing nice with my card.
> > 
> > I should also note that it seems to detect an "NV22" card, with 64M of
> > memory.  I have an NV44 card with 256M of memory.  Oddly enough, it
> > seems to get that number from the PCI device ID, and really doesn't
> > seem to care what it actually *is*.
> > 
> > I'll paste some lspci output, etc., in hopes that it is useful.
> > 
> > lspci for this card:
> > 03:00.0 VGA compatible controller: nVidia Corporation NV44A [GeForce
> > 6200] (rev a1)
> > 
> > dmesg output on module being loaded:
> > nvidiafb: Device ID: 10de0221
> > nvidiafb: CRTC0 analog not found
> > nvidiafb: CRTC1 analog found
> > nvidiafb: EDID found from BUS1
> > i2c-adapter i2c-2: unable to read EDID block.
> > i2c-adapter i2c-2: unable to read EDID block.
> > i2c-adapter i2c-2: unable to read EDID block.
> > nvidiafb: CRTC 0appears to have a CRT attached
> > nvidiafb: Using CRT on CRTC 0
> > nvidiafb: MTRR set to ON
> > Console: switching to colour frame buffer device 160x64
> > nvidiafb: PCI nVidia NV22 framebuffer (64MB @ 0xC0000000)
> > 
> > I should also note that a program that worked JUST FINE on the old
> > hardware using the directfb libraries now randomly segfaults.
> > 
> > --Russell
> > -- 
> > fedora-list mailing list
> > fedora-list redhat com
> > To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list

And before everyone jumps on me, sorry about the top post. I have
returned to work where everything is top posted and I haven't adjusted
to changing gears yet.

Regards,
Les H


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