From: Jon B. <jo...@pr...> - 2008-02-13 20:25:50
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I am trying to use GPIO17 on a verdex gumstix as an output GPIO line. However, 10 minutes and 3 seconds after power-on, some process is setting this GPIO line low. I have a couple of gumstix, and I only get this behavior on my gumstix that have buildroot 1559. Another gumstix with buildroot 1407 does not have this problem. Originally I thought it was a problem with something that I had done, so I removed all of the code that I had added to the gumstix. When that didn't work, I started removing drivers and processes. Eventually I just pulled a brand-new gumstix out of the box, plugged it into a standard console-vx and tried again, with the same behavior. Here is the full process after login: # echo "GPIO out set">/proc/gpio/GPIO17 # more /proc/gpio/GPIO17 17 GPIO out set # date Wed Dec 31 16:08:50 PST 1969 # more /proc/gpio/GPIO17 17 GPIO out set # date Wed Dec 31 16:10:02 PST 1969 # more /proc/gpio/GPIO17 17 GPIO out set # date Wed Dec 31 16:10:04 PST 1969 # more /proc/gpio/GPIO17 17 GPIO out clear Again, this is happening with a brand-new verdex gumstix. I haven't changed anything except for the setting of that one GPIO17 line, as shown above. I don't know if this is happening with other GPIO lines. I only noticed it because this particular line was controlling something, and I noticed when it turned off. The Hirose 60-pin connector indicates that GPIO17 is also the PWM1 signal, but it's not obvious to me that something would be trying to drive the PWM signal either, much less only once, 10 minutes after power-on. One other difference that I noticed between the 1407 board and the 1559 boards was that GPIO17 defaults to be an input on the 1559 build, but defaults to be an output in the "cleared" state on the 1407 build. If anyone has any idea what might be setting GPIO17 low 10 minutes after power-on, I would love to find out. I could always move to another GPIO line, but it's somewhat unnerving. If I don't know what's causing this line to be set low, it lessens my confidence that this won't happen with some other GPIO line as well. Thanks in advance! -- View this message in context: http://www.nabble.com/GPIO17-output-set-low-10-minutes-after-power-on-tp15446665p15446665.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Chris D. <chr...@gm...> - 2008-02-13 20:40:29
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Looking at the pxafb-definition.patch for the kernel it appears that the verdex uses gpio 17 to control the backlight on the samsung lcd, so I'm guessing that is the culprit in your case. Are you using the samsung lcd in your setup? I'd assume not...? Chris On Feb 13, 2008 1:25 PM, Jon Bosley <jo...@pr...> wrote: > > I am trying to use GPIO17 on a verdex gumstix as an output GPIO line. > However, 10 minutes and 3 seconds after power-on, some process is setting > this GPIO line low. I have a couple of gumstix, and I only get this > behavior on my gumstix that have buildroot 1559. Another gumstix with > buildroot 1407 does not have this problem. > > Originally I thought it was a problem with something that I had done, so I > removed all of the code that I had added to the gumstix. When that didn't > work, I started removing drivers and processes. Eventually I just pulled a > brand-new gumstix out of the box, plugged it into a standard console-vx and > tried again, with the same behavior. > > Here is the full process after login: > # echo "GPIO out set">/proc/gpio/GPIO17 > # more /proc/gpio/GPIO17 > 17 GPIO out set > # date > Wed Dec 31 16:08:50 PST 1969 > # more /proc/gpio/GPIO17 > 17 GPIO out set > # date > Wed Dec 31 16:10:02 PST 1969 > # more /proc/gpio/GPIO17 > 17 GPIO out set > # date > Wed Dec 31 16:10:04 PST 1969 > # more /proc/gpio/GPIO17 > 17 GPIO out clear > > Again, this is happening with a brand-new verdex gumstix. I haven't changed > anything except for the setting of that one GPIO17 line, as shown above. I > don't know if this is happening with other GPIO lines. I only noticed it > because this particular line was controlling something, and I noticed when > it turned off. The Hirose 60-pin connector indicates that GPIO17 is also > the PWM1 signal, but it's not obvious to me that something would be trying > to drive the PWM signal either, much less only once, 10 minutes after > power-on. > > One other difference that I noticed between the 1407 board and the 1559 > boards was that GPIO17 defaults to be an input on the 1559 build, but > defaults to be an output in the "cleared" state on the 1407 build. > > If anyone has any idea what might be setting GPIO17 low 10 minutes after > power-on, I would love to find out. I could always move to another GPIO > line, but it's somewhat unnerving. If I don't know what's causing this line > to be set low, it lessens my confidence that this won't happen with some > other GPIO line as well. > > Thanks in advance! > -- > View this message in context: http://www.nabble.com/GPIO17-output-set-low-10-minutes-after-power-on-tp15446665p15446665.html > Sent from the Gumstix mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Jon B. <jo...@pr...> - 2008-02-13 20:48:44
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Chris, I am not using an LCD screen. I had seen that GPIO17 could be used for a backlight, but I didn't see any indication of any process that would be controlling that. I saw a message on how to turn the backlight off through /sys/class/graphics/fb0/blank, but the /sys/class/graphics directory doesn't exist (presumably because I don't have an LCD), so I figured that wasn't it. But perhaps it is. -- View this message in context: http://www.nabble.com/GPIO17-output-set-low-10-minutes-after-power-on-tp15446665p15467569.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Chris D. <chr...@gm...> - 2008-02-13 21:27:06
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Looking at the defconfig for verdex it seems that support for the samsung is built into the kernel. Mabye that change happened between the 2 revisions that work/don't. Can you check your kernel config just to be sure? Chris On Feb 13, 2008 1:48 PM, Jon Bosley <jo...@pr...> wrote: > > Chris, > > I am not using an LCD screen. I had seen that GPIO17 could be used for a > backlight, but I didn't see any indication of any process that would be > controlling that. I saw a message on how to turn the backlight off through > /sys/class/graphics/fb0/blank, but the /sys/class/graphics directory doesn't > exist (presumably because I don't have an LCD), so I figured that wasn't it. > But perhaps it is. > -- > View this message in context: http://www.nabble.com/GPIO17-output-set-low-10-minutes-after-power-on-tp15446665p15467569.html > > Sent from the Gumstix mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Jon B. <jo...@pr...> - 2008-02-13 22:03:45
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I haven't replaced the buildroot on these gumstix. I set up the buildroot on my computer prior to the date of the buildroot on these gumstix, and haven't changed it since. I am not very familiar with configuring the kernel. When I run "make menuconfig" in my gumstix-buildroot/build_arm_nofpu/linux-2.6.21gum directory, under Device Drivers, Graphics support, there is an option for "Backlight and LCD device support", which is not selected. However, I don't know how much that means since the gumstix don't have that buildroot on them. Chris Dollar wrote: > > Looking at the defconfig for verdex it seems that support for the > samsung is built into the kernel. Mabye that change happened between > the 2 revisions that work/don't. Can you check your kernel config > just to be sure? > > Chris > -- View this message in context: http://www.nabble.com/GPIO17-output-set-low-10-minutes-after-power-on-tp15446665p15469070.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Chris D. <chr...@gm...> - 2008-02-13 22:26:54
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Yes, I'm not sure if its relevant since you're running a stock setup, and I'm not sure how you could check to see if it was the case. Sorry I can't be of more help there - I just figured checking out the lcd backlight stuff would be a good place to start :) Mabye someone else has some ideas? Chris On Feb 13, 2008 3:03 PM, Jon Bosley <jo...@pr...> wrote: > > I haven't replaced the buildroot on these gumstix. I set up the buildroot on > my computer prior to the date of the buildroot on these gumstix, and haven't > changed it since. I am not very familiar with configuring the kernel. When > I run "make menuconfig" in my > gumstix-buildroot/build_arm_nofpu/linux-2.6.21gum directory, under Device > Drivers, Graphics support, there is an option for "Backlight and LCD device > support", which is not selected. However, I don't know how much that means > since the gumstix don't have that buildroot on them. > > > > Chris Dollar wrote: > > > > Looking at the defconfig for verdex it seems that support for the > > samsung is built into the kernel. Mabye that change happened between > > the 2 revisions that work/don't. Can you check your kernel config > > just to be sure? > > > > Chris > > > > -- > View this message in context: http://www.nabble.com/GPIO17-output-set-low-10-minutes-after-power-on-tp15446665p15469070.html > > Sent from the Gumstix mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |