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Is there a way to force probe to be called (etherned driver) ?
by Ran Shalit July 24, 2016

July 24, 2016

Hello, I write ethernet driver (mac controller is implemented in fpga connected to cpu) I see that the probe is not called on doing insmod. Is there a way to force the probe to be called on doing insmod ? I could not find in the board file (omap dart, kernel 3.4.0) any reference to ethernet. Best Regards, Ran

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Re: Mapping of Filename to allocated blocks
by Manoj Rao July 22, 2016

July 22, 2016

Thank you Valids. That worked! For others who may look for this info: If you have access to the struct file * then you could obtain this info with the following condition check: ============================================ struct file *filp = <blah blah>; if (filp->f_path.mnt->mnt_flags & MNT_NODEV) pr_info("ramfs node\n"); else pr_info("persist storage backed node\n"); ============================================ On Wed, Jul 20, 2016 at 7:49 PM, <Valdis.Kletnieks(a)vt.edu> wrote: > On Wed, 20 Jul 2016 18:46:47 -0700, Manoj Rao said: > > > However, I need to run this for each and every read system call which > > includes all the procfs, sysfs and other RAM fs based file reads. My > > code is causing the kernel to panic at some point due to an illegal > > memory access while trying to obtain the starting sector/block for the > > file that's currently being read. My hunch is the crash occurs when > > file being read is on a non-persistent fs such as a sysfs node > > I have gotten hold of the inode structure and I'm trying to find if > > a given inode is stored persistently or not and I've been unable to > > find this information so far. > > Hint: First, check if the filesystem is a pseudo filesystem before > bothering > to look for baking store. If you need to know how to do that, steal the > code from the code that prints /proc/filesystems - if it says 'nodev', > you'll > only find pain looking for backing storage. >

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lightweight live os for bisect
by Matwey V. Kornilov July 21, 2016

July 21, 2016

Hello, I would like to make a long-range bisect (unfortunately) to find where an issue appeared. The issue is present only on single one laptop, where I don't want to alter OS or somehow intrude things. Moreover, when I usually do `git bisect' between subsequent releases, I am fine with ordinarily 'make install', which is not the case now, because, for instance, 2.6.xx just won't run with modern systemd things (or, correctly, systemd things won't run with 2.6.xx). So, I would like to discover a way to compile USB live image with as simple as possible OS using precompiled ./linux tree. Only my test executable is required to run after the boot to show whether the issue here. So, what would you recommend? Or, how do you solve such problem usually?

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Re: gpio-led driver
by Gadre Nayan July 21, 2016

July 21, 2016

Hi, I used this: /* * XXX: Use a flat representation of the AM33XX interconnect. * The real AM33XX interconnect network is quite complex.Since * that will not bring real advantage to represent that in DT * for the moment, just use a fake OCP bus entry to represent * the whole bus hierarchy. */ ocp { compatible = "simple-bus"; #address-cells = <1>; #size-cells = <1>; ranges; ti,hwmods = "l3_main"; . . . dali_gpio { compatible = "arm,dali_gpio"; dali_TX = <9>; dali_RX = <10>; }; } Thanks Nayan Gadre. On Thu, Jul 21, 2016 at 11:19 AM, Raul Piper <raulpblooper(a)gmail.com> wrote: > kindly cc the previous people in "To" .Sorry I missed in while replying you. > > On Thu, Jul 21, 2016 at 11:17 AM, Raul Piper <raulpblooper(a)gmail.com> wrote: >> HI, >> >> On Thu, Jul 21, 2016 at 9:43 AM, Gadre Nayan <gadrenayan(a)gmail.com> wrote: >>> Hi, >>> >>> OF stands for open firmware, OF uses a format to represent platform >>> information, which is called a device tree. >>> >>> An example of how the driver extracts information from device tree: >>> >>> #if defined(CONFIG_OF) >>> static const struct of_device_id dali_of_ids[] = >>> { >>> { .compatible = "arm,dali_gpio", }, >>> {}, >>> }; >>> >>> MODULE_DEVICE_TABLE(of, dali_of_ids); >>> #endif >>> >>> static struct platform_driver dali_driver = { >>> .driver = { >>> .name = "dali_gpio", >>> .of_match_table = of_match_ptr(dali_of_ids), >>> }, >>> .probe = Dali_probe, >>> .remove = Dali_remove, >>> }; >>> >>> The driver is going to fetch information from the device tree later on >>> (in probe) using the compatible property mentioned. So if the tree has >>> the same compatible string then subsequent information can be obtained >>> from that device tree node. >>> >>> Thanks >>> >> Can you please post the coresponding dt binding code? >> >>> On Thu, Jul 21, 2016 at 9:42 AM, Gadre Nayan <gadrenayan(a)gmail.com> wrote: >>>> Hi, >>>> >>>> OF stands for open firmware, OF uses a format to represent platform >>>> information, which is called a device tree. >>>> >>>> An example of how the driver extracts information from device tree: >>>> >>>> #if defined(CONFIG_OF) >>>> static const struct of_device_id dali_of_ids[] = >>>> { >>>> { .compatible = "arm,dali_gpio", }, >>>> {}, >>>> }; >>>> >>>> MODULE_DEVICE_TABLE(of, dali_of_ids); >>>> #endif >>>> >>>> static struct platform_driver dali_driver = { >>>> .driver = { >>>> .name = "dali_gpio", >>>> .of_match_table = of_match_ptr(dali_of_ids), >>>> }, >>>> .probe = Dali_probe, >>>> .remove = Dali_remove, >>>> }; >>>> >>>> The driver is going to fetch information from the device tree later on >>>> (in probe) using the compatible property mentioned. So if the tree has >>>> the same compatible string then subsequent information can be obtained >>>> from that device tree node. >>>> >>>> Thanks >>>> Nayan Gadre >>>> >>>> On Wed, Jul 20, 2016 at 8:30 PM, Anish Kumar >>>> <anish198519851985(a)gmail.com> wrote: >>>>> >>>>> >>>>> On Jul 20, 2016, at 4:15 AM, Raul Piper <raulpblooper(a)gmail.com> wrote: >>>>> >>>>> Hi, >>>>> I wanted to know the part number >>>>> >>>>> >>>>> What is part number? >>>>> >>>>> for the leds-gpio.c in the driver/leds folder and the device tree bindings >>>>> for this driver .Can some one point out to me where in Linux kernel it is? >>>>> >>>>> Also why below line has been used.Is it mandatory? >>>>> ... >>>>> .of_match_table = of_gpio_leds_match, >>>>> >>>>> >>>>> This is needed when you are using device tree for getting the board settings >>>>> but you can also do the same without this as well. Read up on device tree in >>>>> kernel Documentation folder. >>>>> >>>>> }, >>>>> >>>>> thanks in advance , >>>>> Rp >>>>> >>>>> _______________________________________________ >>>>> Kernelnewbies mailing list >>>>> Kernelnewbies(a)kernelnewbies.org >>>>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>>>> >>>>> >>>>> _______________________________________________ >>>>> Kernelnewbies mailing list >>>>> Kernelnewbies(a)kernelnewbies.org >>>>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>>>>

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gpio-led driver
by Raul Piper July 21, 2016

July 21, 2016

Hi, I wanted to know the part number for the leds-gpio.c in the driver/leds folder and the device tree bindings for this driver .Can some one point out to me where in Linux kernel it is? Also why below line has been used.Is it mandatory? ... *.of_match_table = of_gpio_leds_match,* }, thanks in advance , Rp

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Mapping of Filename to allocated blocks
by Manoj Rao July 21, 2016

July 21, 2016

Hi All, I'm looking for a way to get a filename associated with a given physical block (ideally what I'd like is a mapping of filename <=> all the allocated blocks for this file). Is there a recommended way to do this already in kernel? if not, then where should I start looking to add changes? Help appreciated. Thanks.

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How do you test Linux kernel?
by Aleksander Alekseev July 20, 2016

July 20, 2016

Hello It is my understanding that Linux kernel doesn't has usual `make check` or `make test` command. There are LTP [1] and other related projects instead. Could you tell me please what test suits (if any) do _you_ run in practice? [1] http://linux-test-project.github.io/ -- Best regards, Aleksander Alekseev

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How old Linux Device Drivers 3 book is now?
by Fernando França July 20, 2016

July 20, 2016

Hi everyone. I'm a totally fresh and newbie with kernel development and I've started reading Linux Device Drivers 3 book (CORBET et al). Since this book approaches is based on kernel 2.6 and we are currently with kernel 4.x, someone could help me telling if this book is still a good introduction to the subject, or is now highly outdated? Thanks in advance. -- Fernando França http://desconstruindo.eng.br Linux user #263682 Dificultando a vida dos usuários desde 1999

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kgdb on kernel4.4 for arm
by Pankaj Gupta July 20, 2016

July 20, 2016

Hello all, I am trying to use kgdboc on arm64 based kernel 4.4 android device, but could not able to connect it. Is anyone have used kgdb on arm based android devices? Thanks & Regards, *Pankaj Gupta*

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Pending work related to kernel for a newbie
by Ashijeet Acharya July 20, 2016

July 20, 2016

Hi everyone, I am kernel newbie and I was looking for something to work upon to improve my skill-set. I have good knowledge of C and experience in writing patches. Also please refer me if there is a to-do list for newbies related to pending tasks for linux kernel. Thanks Ashijeet

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