Bjørn Mork 3edce1cf81 USB: cdc-wdm: implement IOCTL_WDM_MAX_COMMAND ... Userspace applications need to know the maximum supported message size. The cdc-wdm driver translates between a character device stream and a message based protocol. Each message is transported as a usb control message with no further encapsulation or syncronization. Each read or write on the character device should translate to exactly one usb control message to ensure that message boundaries are kept intact. That means that the userspace application must know the maximum message size supported by the device and driver, making this size a vital part of the cdc-wdm character device API. CDC WDM and CDC MBIM functions export the maximum supported message size through CDC functional descriptors. The cdc-wdm and cdc_mbim drivers will parse these descriptors and use the value chosen by the device. The only current way for a userspace application to retrive the value is by duplicating the descriptor parsing. This is an unnecessary complex task, and application writers are likely to postpone it, using a fixed value and adding a "todo" item. QMI functions have no way to tell the host what message size they support. The qmi_wwan driver use a fixed value based on protocol recommendations and observed device behaviour. Userspace applications must know and hard code the same value. This scheme will break if we ever encounter a QMI device needing a device specific message size quirk. We are currently unable to support such a device because using a non default size would break the implicit userspace API. The message size is currently a hidden attribute of the cdc-wdm userspace API. Retrieving it is unnecessarily complex, increasing the possibility of drivers and applications using different limits. The resulting errors are hard to debug, and can only be replicated on identical hardware. Exporting the maximum message size from the driver simplifies the task for the userspace application, and creates a unified information source independent of device and function class. It also serves to document that the message size is part of the cdc-wdm userspace API. This proposed API extension has been presented for the authors of userspace applications and libraries using the current API: libmbim, libqmi, uqmi, oFono and ModemManager. The replies were: Aleksander Morgado: "We do really need max message size for MBIM; and as you say, it may be good to have the max message size info also for QMI, so the new ioctl seems a good addition. So +1 from my side, for what it's worth." Dan Williams: "Yeah, +1 here. I'd prefer the sysfs file, but the fact that that doesn't work for fd passing pretty much kills it." No negative replies are so far received. Cc: Aleksander Morgado <aleksander@lanedo.com> Cc: Dan Williams <dcbw@redhat.com> Signed-off-by: Bjørn Mork <bjorn@mork.no> Acked-by: Oliver Neukum <oliver@neukum.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2013-03-25 13:32:20 -07:00
..
ABI	Merge branch 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86	2013-03-03 10:16:19 -08:00
DocBook	Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux	2013-02-25 16:46:44 -08:00
EDID	drm: Load EDID: Explain better how to write your own EDID firmware	2013-01-20 19:22:19 +10:00
PCI	PCI/MSI: Enable multiple MSIs with pci_enable_msi_block_auto()	2013-01-24 17:25:13 +01:00
RCU	Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD	2012-11-16 09:59:58 -08:00
accounting	doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c	2012-11-26 14:22:21 +01:00
acpi	ACPI / Documentation: refer to correct file for acpi_platform_device_ids[] table	2013-02-13 13:43:02 +01:00
aoe	aoe: allow user to disable target failure timeout	2012-12-17 17:15:25 -08:00
arm	fbdev changes for 3.8:	2012-12-15 13:03:48 -08:00
arm64	arm64: Add simple earlyprintk support	2013-01-22 17:51:01 +00:00
auxdisplay	…
backlight	backlight: lp855x_bl: support new LP8557 device	2013-02-21 17:22:25 -08:00
blackfin	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
block	cfq-iosched: enable full blkcg hierarchy support	2013-01-09 08:05:11 -08:00
blockdev	nbd: update documentation and link to mailinglist	2013-02-27 19:10:22 -08:00
bus-devices	ARM: OMAP2+: gpmc: generic timing calculation	2012-11-09 18:07:11 +05:30
cdrom	doc: fix broken references	2011-09-27 18:08:04 +02:00
cgroups	Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block	2013-02-28 12:52:24 -08:00
connector	connector: Move cn_test.c away from NLMSG_PUT().	2012-06-26 21:19:02 -07:00
console	…
cpu-freq	cpufreq: Update Documentation for cpus and related_cpus	2013-02-02 00:01:16 +01:00
cpuidle	Honor state disabling in the cpuidle ladder governor	2012-09-04 01:35:44 +02:00
cris	CRIS: Update documentation	2012-04-03 13:09:18 +02:00
crypto	KEYS: Document asymmetric key type	2012-10-08 13:50:12 +10:30
development-process	Documentation: Update stable address	2011-12-12 14:14:31 -08:00
device-mapper	md updates for 3.9	2013-03-05 17:22:08 -08:00
devicetree	Merge 3.9-rc4 into usb-next	2013-03-25 10:05:37 -07:00
driver-model	lib: devres: Introduce devm_ioremap_resource()	2013-01-22 09:41:43 -08:00
dvb	[media] get_dvb_firmware: Fix the location of firmware for Terratec HTC	2013-01-01 11:18:26 -02:00
early-userspace	…
extcon	Documentation/extcon: porting guide for Android kernel switch driver.	2012-04-20 09:24:27 -07:00
fault-injection	doc: fix quite a few typos within Documentation	2012-11-19 14:28:24 +01:00
fb	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
filesystems	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-02-26 20:16:07 -08:00
firmware_class	firmware loader: document firmware cache mechanism	2012-11-14 15:07:18 -08:00
frv	doc: fix broken references	2011-09-27 18:08:04 +02:00
hid	HID: remove x bit from sensor doc	2012-12-14 08:48:59 +01:00
hwmon	hwmon: (lm75) Fix tcn75 prefix	2013-03-18 21:19:49 +01:00
i2c	i2c: Fix my e-mail address in drivers and documentation	2013-03-22 11:18:34 +01:00
i2o	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
ia64	doc: aliasing-test: close fd on write error	2012-09-01 09:57:10 -07:00
ide	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
infiniband	IB/ipoib: Add rtnl_link_ops support	2012-09-20 16:49:17 -04:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2013-03-11 07:49:37 -07:00
ioctl	USB: cdc-wdm: implement IOCTL_WDM_MAX_COMMAND	2013-03-25 13:32:20 -07:00
isdn	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
ja_JP	…
kbuild	Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2013-02-27 12:28:30 -08:00
kdump	kexec: update URL of kexec homepage	2012-07-18 18:35:57 -07:00
ko_KR	driver-core: documentation: fix up Greg's email address	2012-02-15 14:48:01 -08:00
laptops	Documentation/laptops: remove depends on CONFIG_EXPERIMENTAL	2013-01-21 14:52:42 -08:00
leds	Documentation: leds: update LP55xx family devices	2013-02-06 15:59:30 -08:00
m68k	Documentation: add pointer to name_to_dev_t for root= values	2011-08-03 14:25:21 -10:00
make	…
memory-devices	memory: emif: add basic infrastructure for EMIF driver	2012-05-02 00:10:49 -07:00
metag	metag: Basic documentation	2013-03-02 20:09:50 +00:00
mips	…
misc-devices	doc: fix quite a few typos within Documentation	2012-11-19 14:28:24 +01:00
mmc	mmc: core: Extend sysfs to ext_csd parameters for RPMB support	2012-12-06 13:54:48 -05:00
mn10300	…
mtd	…
namespaces	userns: Recommend use of memory control groups.	2013-01-26 22:20:06 -08:00
netlabel	…
networking	net: docs: document multiqueue tuntap API	2013-03-06 14:56:10 -05:00
nfc	NFC: Update pn544 documentation	2013-01-10 01:27:46 +01:00
parisc	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
pcmcia	…
power	PM / OPP: improve introductory documentation	2013-03-04 14:23:11 +01:00
powerpc	powerpc: Documentation for transactional memory on powerpc	2013-02-15 17:02:25 +11:00
pps	…
prctl	seccomp: Make syscall skipping and nr changes more consistent	2012-10-02 21:14:29 +10:00
pti	…
ptp	…
rapidio	RapidIO: documentation update	2011-11-02 16:07:02 -07:00
s390	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
scheduler	sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW	2012-09-13 16:52:04 +02:00
scsi	[SCSI] megaraid_sas: Version and Changelog update	2013-02-22 15:37:15 +00:00
security	Documentation: fix Documentation/security/00-INDEX	2012-12-17 17:15:22 -08:00
serial	tty: Update serial core API documentation	2013-01-15 21:57:44 -08:00
sh	…
sound	ALSA: documentation: Fix typo in Documentation/sound	2013-03-17 10:12:13 +01:00
spi	Documentation: remove __dev* attributes.	2013-01-03 15:57:16 -08:00
sysctl	Documentation/sysctl/kernel.txt: document /proc/sys/shmall	2013-01-04 16:11:46 -08:00
target	target: Simplify fabric sense data length handling	2012-09-17 17:12:58 -07:00
thermal	Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux	2013-02-28 19:48:26 -08:00
timers	doc: fix broken references	2011-09-27 18:08:04 +02:00
trace	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-03-11 07:54:29 -07:00
usb	USB: report submission of active URBs	2012-11-11 18:10:46 -08:00
vDSO	…
video4linux	[media] radio-si470x doc: add info about v4l2-ctl and sox+alsa	2013-02-13 17:33:20 -02:00
virtual	Merge tag 'kvm-3.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2013-02-24 13:07:18 -08:00
vm	ksm: add some comments	2013-02-23 17:50:23 -08:00
w1	w1: w1_therm: Add force-pullup option for "broken" sensors	2013-02-18 13:55:24 -08:00
watchdog	watchdog: core: dt: add support for the timeout-sec dt property	2013-03-01 12:48:36 +01:00
wimax	…
x86	Merge branch 'x86/microcode' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-02-22 19:22:52 -08:00
xtensa	xtensa: initialize atomctl SR	2012-12-18 21:10:22 -08:00
zh_CN	Driver core patches for 3.9-rc1	2013-02-21 12:05:51 -08:00
.gitignore	…
00-INDEX	ImgTec Meta architecture changes for v3.9-rc1	2013-03-03 12:06:09 -08:00
BUG-HUNTING	…
Changes	…
CodingStyle	Documentation: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:38:03 -08:00
DMA-API-HOWTO.txt	Documentation/DMA-API-HOWTO.txt: fix typo	2013-02-27 19:10:23 -08:00
DMA-API.txt	dma-debug: New interfaces to debug dma mapping errors	2012-10-24 17:06:43 +02:00
DMA-ISA-LPC.txt	…
DMA-attributes.txt	common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute	2012-11-29 03:30:34 -08:00
HOWTO	HOWTO: fix double words typo	2012-12-10 15:54:27 +01:00
IPMI.txt	ipmi: add options to disable openfirmware and PCI scanning	2013-02-27 19:10:21 -08:00
IRQ-affinity.txt	…
IRQ-domain.txt	irqdomain: update documentation	2012-12-05 23:52:10 +00:00
IRQ.txt	…
Intel-IOMMU.txt	…
Makefile	mei: move doc files Documentation/misc-devices/mei	2012-05-09 13:59:09 -07:00
ManagementStyle	Documentation: ManagementStyle: fixed typo	2012-06-28 12:03:15 +02:00
SAK.txt	…
SM501.txt	…
SecurityBugs	…
SubmitChecklist	…
SubmittingDrivers	Documentation: SubmittingDrivers: fix Linus's git tree URL	2011-08-13 18:34:03 -07:00
SubmittingPatches	Randy has moved	2013-03-08 15:05:34 -08:00
VGA-softcursor.txt	…
applying-patches.txt	…
atomic_ops.txt	Documentation: Memory barrier semantics of atomic_xchg()	2013-01-08 14:14:55 -08:00
bad_memory.txt	…
basic_profiling.txt	…
binfmt_misc.txt	…
braille-console.txt	…
bt8xxgpio.txt	…
btmrvl.txt	…
bus-virt-phys-mapping.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
cachetlb.txt	…
circular-buffers.txt	…
clk.txt	Documentation: common clk API	2012-03-16 20:35:01 +00:00
coccinelle.txt	coccicheck: Allow the user to give a V= (verbose) argument	2013-02-22 11:39:13 +01:00
cpu-hotplug.txt	doc: Add x86 CPU0 online/offline feature	2012-11-14 09:39:44 -08:00
cpu-load.txt	…
cputopology.txt	…
crc32.txt	crc32: move long comment about crc32 fundamentals to Documentation/	2012-03-23 16:58:37 -07:00
dcdbas.txt	…
debugging-modules.txt	…
debugging-via-ohci1394.txt	…
dell_rbu.txt	…
devices.txt	firmware: remove last vestiges of dabusb	2012-11-21 13:03:01 -08:00
digsig.txt	crypto: digital signature verification support	2011-11-09 12:10:37 +02:00
dma-buf-sharing.txt	dma-buf: implement vmap refcounting in the interface logic	2013-02-27 15:13:36 +05:30
dmaengine.txt	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
dontdiff	x86: remove offsets.h from .gitignore and dontdiff	2012-11-19 14:10:53 +01:00
dynamic-debug-howto.txt	dynamic_debug: dynamic hex dump	2013-01-17 12:19:09 -08:00
edac.txt	Merge branch 'devel'	2012-07-29 21:11:05 -03:00
eisa.txt	MCA: delete all remaining traces of microchannel bus support.	2012-05-17 19:06:13 -04:00
email-clients.txt	Documentation: email-clients: Add better Thunderbird information	2011-08-13 18:34:03 -07:00
flexible-arrays.txt	…
futex-requeue-pi.txt	…
gcov.txt	…
gpio.txt	gpiolib: provide provision to register pin ranges	2012-11-11 19:06:00 +01:00
highuid.txt	…
hw_random.txt	…
hwspinlock.txt	hwspinlock/core: register a bank of hwspinlocks in a single API call	2011-09-21 19:45:34 +03:00
init.txt	…
initrd.txt	Documentation/initrd.txt: Change the location of util-linux	2012-05-25 16:18:34 +02:00
intel_txt.txt	Documentation: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:38:03 -08:00
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	…
irqflags-tracing.txt	…
isapnp.txt	…
java.txt	…
kernel-doc-nano-HOWTO.txt	Kernel-doc: Convention: Use a "Return" section to describe return values	2012-11-27 21:08:57 +01:00
kernel-docs.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
kernel-parameters.txt	ImgTec Meta architecture changes for v3.9-rc1	2013-03-03 12:06:09 -08:00
kmemcheck.txt	…
kmemleak.txt	kmemleak: Handle percpu memory allocation	2011-12-02 16:12:42 +00:00
kobject.txt	Documentation: Fix "struct kobj_type" to include newer members.	2012-09-04 16:06:34 -07:00
kprobes.txt	…
kref.txt	kref: Add kref_get_unless_zero documentation	2012-11-28 18:36:06 +10:00
ldm.txt	…
local_ops.txt	…
lockdep-design.txt	lockdep: Update documentation for lock-class leak detection	2011-12-11 10:31:23 -08:00
lockstat.txt	locking/stat: Fix a typo	2013-02-19 08:42:37 +01:00
lockup-watchdogs.txt	watchdog: Update documentation	2012-02-11 15:11:28 +01:00
logo.gif	…
logo.txt	…
magic-number.txt	wanrouter: completely decouple obsolete code from kernel.	2013-01-31 19:20:33 -05:00
md.txt	md: create externally visible flags for supporting hot-replace.	2011-12-23 10:17:51 +11:00
media-framework.txt	[media] Documentation/media-framework.txt: fix a sentence	2013-02-08 13:27:13 -02:00
memory-barriers.txt	Documentation: Memory barrier semantics of atomic_xchg()	2013-01-08 14:14:55 -08:00
memory-hotplug.txt	hotplug: update nodemasks management	2012-12-12 17:38:33 -08:00
mono.txt	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
mutex-design.txt	…
nommu-mmap.txt	…
numastat.txt	Doc: Update numastat.txt	2012-02-28 16:05:06 +01:00
oops-tracing.txt	module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree	2011-11-07 07:54:42 +10:30
padata.txt	…
parport-lowlevel.txt	…
parport.txt	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
percpu-rw-semaphore.txt	percpu-rw-semaphore: fix documentation typos	2012-09-26 19:56:15 +02:00
pi-futex.txt	…
pinctrl.txt	drivers/pinctrl: grab default handles from device core	2013-01-23 16:39:51 +01:00
pnp.txt	…
preempt-locking.txt	…
printk-formats.txt	Randy has moved	2013-03-08 15:05:34 -08:00
pwm.txt	pwm: add devm_pwm_get() and devm_pwm_put()	2012-09-10 17:05:45 +02:00
ramoops.txt	pstore/ftrace: Convert to its own enable/disable debugfs knob	2012-09-06 22:16:58 -07:00
rbtree.txt	rbtree: move augmented rbtree functionality to rbtree_augmented.h	2012-10-09 16:22:40 +09:00
remoteproc.txt	remoteproc: add rproc_report_crash function to notify rproc crashes	2012-09-18 12:53:22 +03:00
rfkill.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	Documentation: remove __dev* attributes.	2013-01-03 15:57:16 -08:00
rt-mutex-design.txt	…
rt-mutex.txt	…
rtc.txt	rtc-proc: permit the /proc/driver/rtc device to use other devices	2012-10-06 03:05:01 +09:00
serial-console.txt	…
sgi-ioc4.txt	…
sgi-visws.txt	…
smsc_ece1099.txt	mfd: smsc: Add support for smsc gpio io/keypad driver	2012-10-01 15:27:48 +02:00
sparse.txt	Documentation/sparse.txt: document context annotations for lock checking	2012-12-17 17:15:23 -08:00
spinlocks.txt	…
stable_api_nonsense.txt	…
stable_kernel_rules.txt	stable: Allow merging of backports for serious user-visible performance issues	2012-06-25 12:11:58 -07:00
static-keys.txt	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
svga.txt	…
sysfs-rules.txt	…
sysrq.txt	sparc64: Add global PMU register dumping via sysrq.	2012-10-16 09:34:01 -07:00
unaligned-memory-access.txt	…
unicode.txt	…
unshare.txt	…
vfio.txt	vfio: Trivial Documentation correction	2012-09-21 10:48:03 -06:00
vgaarbiter.txt	misc latin1 to utf8 conversions	2012-01-02 13:04:55 +01:00
video-output.txt	…
vme_api.txt	VME: Move API documentation to Documentation folder	2012-05-08 16:01:34 -07:00
volatile-considered-harmful.txt	…
workqueue.txt	workqueue: reimplement WQ_HIGHPRI using a separate worker_pool	2012-07-13 22:24:45 -07:00
xz.txt	…
zorro.txt	…