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Possible Sysfs for led class drivers
by Raul Piper Aug. 11, 2016

Aug. 11, 2016

Hi, I have scanned through some of the led sysfs interfaces of my hardware boards inside the /sys/class/leds and found these brightness, max_brightness trigger uevent invert sata I want to know can we add our own custom sysfs interface ? Does there exists a default list of interfaces provided by the led class subsystem? like brightness, max_brightness,trigger,uevent ,etc?? Thanks in advance ! Rgds Rp

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Documentation/DocBook build error.
by Madhu K Aug. 11, 2016

Aug. 11, 2016

Hi All, I was trying to build Documentation/DocBook, but build is failing with below error. what could be the reason for below error?. I am using Ubntu 14.04 LTS, and my kernel version is 4.5.0-rc7 dsp@BLR-PCUB-01141:/usr/src/linux-stable$ sudo make pdfdocs PDF Documentation/DocBook/device-drivers.pdf Using catalogs: /etc/sgml/catalog Using stylesheet: /usr/share/docbook-utils/docbook-utils.dsl#print Working on: /usr/src/linux-stable/Documentation/DocBook/device-drivers.xml openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:55538:7:E: document type does not allow element "sect1" here openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:56585:7:E: document type does not allow element "sect1" here openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:58367:7:E: document type does not allow element "sect1" here openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:58410:7:E: document type does not allow element "sect1" here openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:58834:4:E: non SGML character number 128 openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:58834:5:E: non SGML character number 157 openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:58834:14:E: non SGML character number 128 openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:58834:15:E: non SGML character number 157 openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:59406:7:E: document type does not allow element "sect1" here openjade:/usr/src/linux-stable/Documentation/DocBook/device-drivers.xml:59778:12:E: end tag for "sect1" which is not finished make[1]: *** [Documentation/DocBook/device-drivers.pdf] Error 8 make: *** [pdfdocs] Error 2 dsp@BLR-PCUB-01141:/usr/src/linux-stable$ Regards, Madhu

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probe failed with error -16
by Raul Piper Aug. 10, 2016

Aug. 10, 2016

Hi, I am developing a driver connected via gpios to the beaglebone and starting with the skeleton driver first and will keep adding functionality to it. I have added relevant compatible device tree string in the device tree as well as in the driver like this .I have built the kernel and then inserted the module. Below is the snapshot of my implementation. My of_device_id looks like this >> static const struct of_device_id of_bc_hw_match[] = { { .compatible = "bc,bc-hwxx5", }, {}, }; MODULE_DEVICE_TABLE(of, of_bc_hw_match); static struct platform_driver bc_driver = { .probe = bc_probe, .remove = bc_remove, .driver = { .name = "bc-hw", .of_match_table = of_match_ptr(of_bc_hw_match), }, My Probe Looks like this :>>>> static int bc_probe(struct platform_device *pdev) { struct gpio_bc_platform_data *pdata = dev_get_platdata(&pdev->dev); struct bc_data *pbc_data; int i, ret = 0; if (!pdata) { printk("inside bc_probe \n"); return -EBUSY; } return ret; } On inserting the module I get this on dmesg : inside bc_probe probe failed with error -16 Thanks and Rgds, Rp

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Not receiving interrupts for SPI slave device on x86
by Federico Lorenzi Aug. 9, 2016

Aug. 9, 2016

Hi all, I've been working on a driver [1] for the SPI touchpad / keyboard found in the new 12" Apple MacBooks. While the driver works OK as a polled device, I can't seem to get interrupts working. I'm requesting an IRQ with: result = request_irq(spi->irq, applespi_irq_handler, IRQF_SHARED, "applespi", applespi); which shows up correctly under /proc/interrupts: 14: 0 0 0 0 IR-IO-APIC 14-fasteoi applespi This is the relevant bit from the DSDT of the SPI slave device (rest of the DSDT at [3]): Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, ) { 0x0000000E, } However, no amount of pressing keys will cause an interrupt to happen. While I don't fully understand the packets I'm using to initialize the SPI device, they're an exact copy of what the Windows driver uses on bootup, and they get the same response. I am booting the kernel with intremap=nosid,no_x2apic_optout; without nosid it won't boot at all, and without no_x2apic_optout the result is the same. One theory I have is that the IOAPIC is incorrectly configuring the pin (full dmesg [2]): [ 0.034850] IOAPIC[0]: Set routing entry (2-14 -> 0x3e -> IRQ 14 Mode:0 Active:0 Dest:1) [ 0.034857] IOAPIC[2]: Set IRTE entry (P:1 FPD:0 Dst_Mode:1 Redir_hint:1 Trig_Mode:0 Dlvry_Mode:1 Avail:0 Vector:3F Dest:00000001 SID:F0F8 SQ:0 SVT:0) Compared with IRQ 23 (which is the SPI controller): [ 15.245319] IOAPIC[2]: Set IRTE entry (P:1 FPD:0 Dst_Mode:1 Redir_hint:1 Trig_Mode:0 Dlvry_Mode:1 Avail:0 Vector:53 Dest:00000001 SID:F0F8 SQ:0 SVT:0) [ 15.245321] IOAPIC[0]: Set routing entry (2-23 -> 0x53 -> IRQ 23 Mode:1 Active:1 Dest:1) Similarly, this is the DSDT bit for the SPI controller: Interrupt (ResourceConsumer, Level, ActiveLow, Shared, ,, ) { 0x00000017, } Any suggestions or pointers would be most welcome. Cheers, Federico [1] https://github.com/cb22/macbook12-spi-driver [2] http://paste.ubuntu.com/22851538/ [3] http://paste.ubuntu.com/22851971/

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Udev rule for USB keyboard
by Madhu K Aug. 9, 2016

Aug. 9, 2016

Hi All, Can anybody share the procedure to write an Udev rule to detect the USB keyboard during hot plug. Thanks&regards, Madhu

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one more new Bie
by Madhu K Aug. 9, 2016

Aug. 9, 2016

Hi Saket Sinha, I am also kernel newbie, I started Eucalyptula challenge challenge 4 months back, till now I have completed 4 tasks and submitted result for 5th task two months back, till now I have not received any response from little. So during this time I wanted occupy with other kernel stuff, can please share how to proceed with "TODOs in the staging area drive" you mentioned below.It will be more helpful for me and other newbies to involve in kernel development activity. Thanks&regards, Madhu On Sun, Aug 7, 2016 at 8:24 PM, <kernelnewbies-request(a)kernelnewbies.org> wrote: > Send Kernelnewbies mailing list submissions to > kernelnewbies(a)kernelnewbies.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > or, via email, send a message with subject or body 'help' to > kernelnewbies-request(a)kernelnewbies.org > > You can reach the person managing the list at > kernelnewbies-owner(a)kernelnewbies.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Kernelnewbies digest..." > > > Today's Topics: > > 1. one more new Bie (Anurag Ranjan) > 2. Re: one more new Bie (Saket Sinha) > 3. Re: one more new Bie (Fran?ois) > 4. Re: one more new Bie (Giedrius Statkevi?ius) > 5. Linux Coding style template (Charls D. Chap) > 6. Re: Linux Coding style template (Greg KH) > 7. Re: Are these books outdated? (John Chludzinski) > 8. Re: Linux Coding style template (Charls D. Chap) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 6 Aug 2016 21:43:47 +0530 > From: Anurag Ranjan <anurag.eee(a)gmail.com> > Subject: one more new Bie > To: kernelnewbies(a)kernelnewbies.org > Message-ID: > <CANeted3zQ8vMbk4Nzk77OSz8jaPFRB28bymJh-egSg-SCRcerA@mail. > gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi All, > > I am new to this list. Please help me with any new bie helper guide. > > How do we get work assigned here? or this is just a query forum. > > Regards, > Anurag >

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Linux Coding style template
by Charls D. Chap Aug. 8, 2016

Aug. 8, 2016

I want to transform some C source files. following Linux kernel coding style. - Does script/Lindent STRICTLY follows all linux kernel coding style rules? - What scripts/templates do you use/suggest for elegant code style with the fact that we are talking about Linux Kernel Coding? The GNU guys suggest indent with the following parameters: -nbad -bap -nbc -bbo -hnl -br -brs -c33 -cd33 -ncdb -ce -ci4 -cli0 -d0 -di1 -nfc1 -i8 -ip0 -l80 -lp -npcs -nprs -npsl -sai -saf -saw -ncs -nsc -sob -nfca -cp33 -ss -ts8 -il1 On the other hand: Linux/script/Lindent contains: -npro -kr -i8 -ts8 -sob -l80 -ss -ncs -cp1 Differences so far: 1) indent with gnu parameters inserts a space on labels eg. err: vs err: 2) indent with gnu parameters inserts 26 spaces #endif /* something like this*/ So probably gnu site is outdated? Also, I have noticed that they both fail theyto leave the empty line of a label empty For example, err: code to err: code What does the coding style suggests in this case? Have you found, other cases such the above?

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Stable and synchronized Time Stamp Counter.
by Gadre Nayan Aug. 8, 2016

Aug. 8, 2016

Hi, I am trying to get the TSC_OFFSET of my guest Qemu machine, Some of the pre-requisites mentioned involve having a Stable TSC (i.e. TSC should not move backawards) So when I enable the write_tsc events in /sys/kernel/debug/tracing/.../kvm_write_tsc_offset I get the following trace: * qemu-system-x86-6668 [003] d... 24541634690432: kvm_write_tsc_offset: vcpu=0 prev=18446721743031245116 next=18446719532074865476* qemu-system-x86-6668 [003] d... 24541659629082: kvm_write_tsc_offset: vcpu=0 prev=18446719532074865476 next=18446719532074865476 * qemu-system-x86-6668 [001] d... 33935995282794: kvm_write_tsc_offset: vcpu=0 prev=18446719532074865476 next=18446710137714276900* qemu-system-x86-6668 [000] d... 33936022496954: kvm_write_tsc_offset: vcpu=0 prev=18446710137714276900 next=18446710137714276900 Here, the prev value is more than the next value, I think this means that my TSC is growing backwards. Is the direction of TSC a configurable option ? How to ensure the TSC grows forwards. Also what does Synchronized TSC mean, how to know if the TSC is synchronized and how to fix it if it not synchronized. Thanks

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one more new Bie
by Anurag Ranjan Aug. 6, 2016

Aug. 6, 2016

Hi All, I am new to this list. Please help me with any new bie helper guide. How do we get work assigned here? or this is just a query forum. Regards, Anurag

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USB gadget mode in laptop
by Susanoo Tux Aug. 5, 2016

Aug. 5, 2016

Hello All, I was looking into USB gadget mode to work on my laptop. One simple basic doubt I have is how do I know whether my USB controller supports gadget mode ? If it supports which module do I need to modprobe ? Found gadget directory here /lib/modules/4.6.4-1-ARCH/kernel/drivers/usb/gadget , but not getting which one to load. Any pointer where I can learn about this more ? Thanks SusanooTux

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