Messages in this thread |  | | | Date | Fri, 21 Jan 2011 09:52:27 -0500 | | From | Alan Ott <> | | Subject | Re: [PATCH 0/1] HID: Report Descriptor in Sysfs |
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On 01/21/2011 04:59 AM, Jiri Kosina wrote: > On Fri, 21 Jan 2011, Alan Ott wrote: > > >> So I'd like to have access to the HID report descriptor in a sysfs entry, so >> I can read it without opening the device. hid-core seemed like the place to >> put it. >> >> Using the /sys/class links, for hidraw devices, this puts a new file, >> report_descriptor in the directory: >> /sys/class/hidraw/hidraw0/device/ >> >> For my USB device (for example), the new file is in: >> /sys/bus/usb/devices/1-5.3:1.0/0003:046D:C216.0001/ >> >> For my Bluetooth device, the new file is in: >> /sys/class/bluetooth/hci0/hci0:11/0005:054C:0268.0002/ >> >> I'm not super confident that these file locations are the best place, but I >> made a best guess so that it could be discussed. The current location is >> where the hid-core stuff lives. Is there a reason these directories are >> named bus:vendor:product:id (instead of hid-core or something similar)? Is >> there a better way to do this? >> > the report descriptor is provided through debugfs HID interface already. > Do you feel like that's not enough? >
Hi Jiri,
Maybe it is. To be honest I didn't check debugfs. I have two concerns about it: 1. Is it wise for userspace programs to rely on: a. debugfs being mounted, b. its mount point, or c. the location or contents of any file in debugfs? 2. /sys/kernel/debug/0003:046D:C216.0002/rdesc is mode 0400 on my system (root-only read). Is there a reason it's so restrictive, or could it be changed to 0444?
Alan.
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