March 2016 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

creating initramfs in fedora
by Ronit Halder March 12, 2016

March 12, 2016

Hi, How can I create a initramfs file without dracut from the files in an installed system in fedora? regards, Ronit

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[PATCH] staging: dgnc: Remove useless and deadly judgment
by Navy Cheng March 11, 2016

March 11, 2016

pci_unregister_driver() should be used once dgnc module exit. It has nothing to do with dgnc_NumBoards. Remove the judgment of dgnc_NumBoards to avoid pci_unregister_driver() is not used when dgnc_NumBoards is 0. Signed-off-by: Navy Cheng <navych(a)126.com> --- drivers/staging/dgnc/dgnc_driver.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/staging/dgnc/dgnc_driver.c b/drivers/staging/dgnc/dgnc_driver.c index fc6d298..20b0c3b 100644 --- a/drivers/staging/dgnc/dgnc_driver.c +++ b/drivers/staging/dgnc/dgnc_driver.c @@ -156,8 +156,7 @@ static void dgnc_cleanup_module(void) dgnc_tty_post_uninit(); - if (dgnc_NumBoards) - pci_unregister_driver(&dgnc_driver); + pci_unregister_driver(&dgnc_driver); } /* -- 2.1.4

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Booting with SYSLINUX on Loopback Device: Kernel Panic - Where to Start?
by Patrick March 9, 2016

March 9, 2016

Hello, I was able to install SYSLINUX on a disk image and get the kernel I built to start booting Linux with QEMU pointing to a loopback device associated with the disk image. However, at some point far into the boot process, I get a kernel panic. I can't read the beginning of the error messages that the kernel prints, because the errors run off the screen. I copied the bzImage onto the disk image, and I'm not sure where to go from there. Is the next step to build the initrd image? I don't yet know how to get the kernel to mount a device so it can find the root file system. Any help is appreciated. Patrick

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kmalloc/malloc for dma ?
by Ran Shalit March 9, 2016

March 9, 2016

Hello, I have some sample code which uses 2 test application: 1. test application in kernel , which allocates buffer using kmalloc (GFP_KERNEL) 2. test application in userspace which allocates buffer using malloc In both cases the buffers are DMA through PCI. I don't understand how is it that the buffers are allocated with malloc/kmalloc for DMA. Is there any idea ? Regards, Ran

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What's wrong with my patch?
by Navy Cheng March 9, 2016

March 9, 2016

Hi, I have sent a patch on 29 Feb, but no reply. I want to know what's wrong with my patch so that I can improve it and myself. my patch is like this: > Date: Mon, 29 Feb 2016 14:41:34 +0800 > From: Navy Cheng <navych(a)126.com> > To: Greg Kroah-Hartman <greg(a)kroah.com> > Cc: Lidza Louina <lidza.louina(a)gmail.com>, kernelnewbies <kernelnewbies(a)kernelnewbies.org> > Subject: [PATCH] staging: dgnc: Remove useless and deadly judgment > User-Agent: Mutt/1.5.23 (2014-03-12) > > pci_unregister_driver() should be used once dgnc module exit. It has > nothing to do with dgnc_NumBoards. Remove the judgment of dgnc_NumBoards to > avoid pci_unregister_driver() is not used when dgnc_NumBoards is 0. > > Signed-off-by: Navy Cheng <navych(a)126.com> > --- > drivers/staging/dgnc/dgnc_driver.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/staging/dgnc/dgnc_driver.c b/drivers/staging/dgnc/dgnc_driver.c > index fc6d298..20b0c3b 100644 > --- a/drivers/staging/dgnc/dgnc_driver.c > +++ b/drivers/staging/dgnc/dgnc_driver.c > @@ -156,8 +156,7 @@ static void dgnc_cleanup_module(void) > > dgnc_tty_post_uninit(); > > - if (dgnc_NumBoards) > - pci_unregister_driver(&dgnc_driver); > + pci_unregister_driver(&dgnc_driver); > } > > /* Thank you :)

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Getting a functional driver for Mad Catz Fightstick TE 2 (Xbox One version)
by Silvan Jegen March 8, 2016

March 8, 2016

Heyho I bought a Mad Catz Fightstick TE2 for Xbox One because I wanted to play some fighting games on Linux. I chose this stick because it has gotten good reviews and I assumed that the Kernel driver should work because there are already drivers for Xbox One controllers in drivers/input/joystick/xpad.c. It turns out that the driver does not work and dmesg just shows [12293.077720] usb 1-1.2.1: new full-speed USB device number 9 using ehci-pci when plugging it in. Simply adding the line { 0x0738, 0x4a01, "Mad Catz FightStick TE 2", 0, XTYPE_XBOXONE }, (where the two Hex values are VENDOR_ID and PRODUCT_ID) to xpad_device[] in xpad.c does not help either (which I naively hoped it would). I realized that the stick does not conform to the USB HID interface after looking more closely at the lsusb -v output (pasted below). Bus 001 Device 007: ID 0738:4a01 Mad Catz, Inc. Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 255 Vendor Specific Subclass bDeviceProtocol 255 Vendor Specific Protocol bMaxPacketSize0 64 idVendor 0x0738 Mad Catz, Inc. idProduct 0x4a01 bcdDevice 0.34 iManufacturer 1 MADCATZ iProduct 2 FIGHTSTICK iSerial 3 0000BCA2F0E774D2 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 32 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xa0 (Bus Powered) Remote Wakeup MaxPower 200mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 71 bInterfaceProtocol 208 iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 4 Device Status: 0x0002 (Bus Powered) Remote Wakeup Enabled The Fightstick seems to use a "Vendor Specific Class" and not the HID interface. The device is relatively simple having only about 10 buttons and a digital stick and the Xbox One driver for Windows works for it so xpad.c should be able to deal with it I assume. Worst case I would have to reverse- engineer the USB protocol it uses on my Window installation though I hope that will not be necessary given that the much more sophisticated Xbox One controller works on Linux already. What I would like to know is if it is possible to use the xpad.c infrastructure in this case and maybe some pointers on where to go from here (I have looked at [0],[1] and [2] but want to check if somebody has dealt with a similar case already and can give me a hint). Thanks! Cheers, Silvan [0] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Docume… [1] https://lwn.net/Kernel/LDD3/ [2] http://matthias.vallentin.net/blog/2007/04/writing-a-linux-kernel-driver-fo…

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GSoC: RFC: fbdev fbtft auxdisplay or IIO
by Martin Kepplinger March 8, 2016

March 8, 2016

Hi GregKH, In looking around what I could do in the mid-future, possibly as a GSoC project (?), I have 2 questions: Is there active ongoing work on getting rid of drivers/auxdisplay? There are 2 drivers left in there... If not, would that be desired? What is the status of fbtft? Moving drivers *in* to staging feels wrong, but fbtft isn't yet present in the main tree. I would guess that fbtft is where these auxdisplay drivers could go. Would you put them into another area? fbdev? Different topic: IIO: I have ideas for mma8452 driver additions, and along this way, additions to the iio sysfs ABI. Would it make sense to lay this out and make a project out of it? Thanks for your time and work, martin -- Martin Kepplinger https://martinkepplinger.com

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Driver duplicate?
by Kenneth Adam Miller March 7, 2016

March 7, 2016

I have a driver that manages three sets of identical data structures that differ only in address values. Currently, I pray that the device file to which I have callbacks mapped for the driver gets called sequentially, because there are pairs of mmap's that need to be made. I know that this isn't the most ideal way to do it, so I'm searching for a better way rather than to swap out the values on each method call. There are several things I am aware of but for each one I have questions: 1) there are kernel module parameters If I use kernel module parameters, I need to be able to insert the kernel module three times in order to have each one have a distinct set of global memory and mapped callbacks to distinct files. Can that be done? Second, I will need to compile the driver statically later. How can I pass those parameters that would otherwise be on the command line in statically? 2) I can compile the driver in three times with a compile time flag. This is the simplest and easiest, but it requires some buildroot and makefile foo that I think is a dirty hack. 3) I could have the init function create three separate files, since it is on init that I discover what my values are. But then I have to also associate identical functions that reference global variables in the kernel object. Duplicating the code would be worse that compiling the same code three times with a kernel parameter, even though that would help me solve my distinct globals problem. So how could I parameterisze a char device with data specific to the instance?

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None
by nunojsa March 7, 2016

March 7, 2016

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ARM Linux: Where the SDRAM address and size defined
by Woody Wu March 7, 2016

March 7, 2016

Hi, In Samsung s3c24xx arch code, I cannot find where the SDRAM address and size information was defined. Can someone give me a lead? Thanks. -woody -- Life is the only flaw in an otherwise perfect nonexistence -- Schopenhauer woody public key at http://subkeys.pgp.net:11371 (narkewoody(a)gmail.com)

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