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Driver with hard RT requiremnets
by Ran Shalit Dec. 5, 2016

Dec. 5, 2016

Hello, We need to support serial driver with real time requirements (towards specific device with RT demands): Every 5.3msec receive 100 bytes and 1.3msec afterwards send 100 bytes. 1. Does kernel support real-time of such hard requirements ? 2. Is it matter if we do the exact bytes send/receive from kernel or userspace, i.e. is kernel more real-time than userspace ? 3. Is mainline kernel unable to support such requirements and we better use RT patch such as xemonai ? Best Regards, Ran

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How to control power of a device from sysfs ?
by Ran Shalit Dec. 5, 2016

Dec. 5, 2016

Hello, I am trying to turn off screen using sysfs entries, but I'm having some difficulties with it: 1. command: echo 0 > /sys/devices/platform/s5p-dsim.0/ea8061/backlight/panel/brightness result: screen is dimmed - BUT not turned off 2. command: cat /sys/devices/platform/s5p-dsim.0/ea8061/backlight/panel/actual_brightness 20 This strengthen the fast that we didn't turned off brightness completely 3. In this point I though that maybe I can turn off the whole brightness device ls /sys/devices/platform/s5p-dsim.0/ea8061/backlight/panel/ actual_brightness auto_brightness bl_power brightness device dimming max_brightness power subsystem type uevent I made some trials , but didn't made it turned off yet. Is there any idea if it's possible to turn it off completely ? Thank you, Ran

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Re: Kernelnewbies Digest, Vol 73, Issue 3
by John Smith Dec. 5, 2016

Dec. 5, 2016

Hi Andrey, Can you help post some good/still relevant links? Call me stupid, I did google, found a few websites, and most of them are kind of out of contexts(don't know how to follow). For beginners, step-by-step tutorials are the best. so far, sounds like kgdb is promising, but it requires a lot of backgrounds to start with. I still have not figured out the exact steps. Thank you, Message: 1 Date: Fri, 2 Dec 2016 23:15:44 +0000 From: Andrey Utkin <andrey_utkin(a)fastmail.com> Subject: Re: Debugging tool for Linux kernel and driver development To: Teoh Choon Zone <choon-zone.teoh(a)vie.com.my> Cc: kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <20161202231544.GB23301(a)dell-m4800.home> Content-Type: text/plain; charset=us-ascii On Fri, Dec 02, 2016 at 03:27:01PM +0800, Teoh Choon Zone wrote: > What are some widely used industrial tools (software/ hardware) for > debugging Linux kernel and driver? Recently my company allocate a budget > for purchasing this kind of tools, so I would like what are the tools that > would greatly ease our development. You'd better budget some time to google a bit and watch conference videos showing debugging techniques :) There are fine videos from past Kernel Recipes conferences.

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unsubscribe
by 조동석 Dec. 5, 2016

Dec. 5, 2016

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Debugging tool for Linux kernel and driver development
by Teoh Choon Zone Dec. 2, 2016

Dec. 2, 2016

What are some widely used industrial tools (software/ hardware) for debugging Linux kernel and driver? Recently my company allocate a budget for purchasing this kind of tools, so I would like what are the tools that would greatly ease our development.

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Re: building last kernel version
by Alexander Kapshuk Dec. 2, 2016

Dec. 2, 2016

On Fri, Dec 2, 2016 at 6:02 AM, Ahmed Adel <ahmd.toulba(a)gmail.com> wrote: > your solution is correct. Thanks you so much You're welcome. Good to hear it worked out for you. Thanks for letting us know.

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building last kernel version
by Ahmed Adel Dec. 1, 2016

Dec. 1, 2016

Hi, I'm trying to build the latest version of kernel. i followed steps on this link https://kernelnewbies.org/KernelBuild .I switched to branch v4.9-rc9 when I check my current branch using command (git status), I get ( On branch v4.9-rc9 ) .when I complete next steps on the page and open .conf file .I find # Linux/x86 4.9.0-rc5 Kernel Configuration . why isn't it # Linux/x86 4.9.0-rc9 Kernel Configuration ?

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Re: Kernel boot panic
by Amit Mahadik Dec. 1, 2016

Dec. 1, 2016

Hi Valdis, Thanks for your prompt answer. I have ext3 builtin the kernel. After looking into the code I found that sys_mknod function fails. I am unable to understand why this happens? Regards,Amit. On Wednesday, 30 November 2016 11:38 PM, "Valdis.Kletnieks(a)vt.edu" <Valdis.Kletnieks(a)vt.edu> wrote: On Wed, 30 Nov 2016 14:12:18 +0000, Amit Mahadik said: > bootargs Kernel command line: console=ttyS0,115200 noinitrd rw rootfstype=ext3 root=/dev/mmcblk0p2 rootwait mem=512M coherent_pool=4M no_console_suspend resume=/dev/mtdblock3. > However, while booting I get the following error > Failed to create /dev/root: -2VFS: Cannot open root device "mmcblk0p2" or unknown-block(179,2): error -2 If you're booting with noinitrd, you better have ext3 as a builtin, not a module, or you're going to have a really bad day....

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Fwd: Question about arp caches
by Anupam Kapoor Nov. 30, 2016

Nov. 30, 2016

FYI ---------- Forwarded message --------- From: Anupam Kapoor <anupam.kapoor(a)gmail.com> Date: Tue, 29 Nov 2016 at 1:25 PM Subject: Re: Question about arp caches To: Shawn Peng <yisupeng(a)gmail.com> On Tue, Nov 29, 2016 at 12:49 PM, Shawn Peng <yisupeng(a)gmail.com> wrote: I find a lot references of the function neigh_release(), can you direct me to the one that releases a staled arp entry? neigh_destroy(...) is probably what you are looking for. -- kind regards anupam -- In the beginning was the lambda, and the lambda was with Emacs, and Emacs was the lambda.

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Question about arp caches
by Shawn Peng Nov. 29, 2016

Nov. 29, 2016

Hi, I'm reading the code about arp protocol. It seems like the kernel uses the neigh_table structure to keep track of caches, right? There should be some code that remove the stale entries in the cache, but I didn't find the code that does this job. Does anyone have an idea? Thanks, Yisu

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