Add a new device quirk that can be used to blacklist endpoints.
Since commit 3e4f8e21c4 ("USB: core: fix check for duplicate
endpoints") USB core ignores any duplicate endpoints found during
descriptor parsing.
In order to handle devices where the first interfaces with duplicate
endpoints are the ones that should have their endpoints ignored, we need
to add a blacklist.
Tested-by: edes <edes@gmx.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20200203153830.26394-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Paul Zimmerman reports that his USB Bluetooth adapter sometimes
crashes following system resume, when it receives a
Get-Device-Descriptor request while it is busy doing something else.
Such a request was added by commit a4f55d8b8c ("usb: hub: Check
device descriptor before resusciation"). It gets sent when the hub
driver's work thread checks whether a connect-change event on an
enabled port really indicates a new device has been connected, as
opposed to an old device momentarily disconnecting and then
reconnecting (which can happen with xHCI host controllers, since they
automatically enable connected ports).
The same kind of thing occurs when a port's power session is lost
during system suspend. When the system wakes up it sees a
connect-change event on the port, and if the child device's
persist_enabled flag was set then hub_activate() sets the device's
reset_resume flag as well as the port's bit in hub->change_bits. The
reset-resume code then takes responsibility for checking that the same
device is still attached to the port, and it does this as part of the
device's resume pathway. By the time the hub driver's work thread
starts up again, the device has already been fully reinitialized and
is busy doing its own thing. There's no need for the work thread to
do the same check a second time, and in fact this unnecessary check is
what caused the problem that Paul observed.
Note that performing the unnecessary check is not actually a bug.
Devices are supposed to be able to send descriptors back to the host
even when they are busy doing something else. The underlying cause of
Paul's problem lies in his Bluetooth adapter. Nevertheless, we
shouldn't perform the same check twice in a row -- and as a nice side
benefit, removing the extra check allows the Bluetooth adapter to work
more reliably.
The work thread performs its check when it sees that the port's bit is
set in hub->change_bits. In this situation that bit is interpreted as
though a connect-change event had occurred on the port _after_ the
reset-resume, which is not what actually happened.
One possible fix would be to make the reset-resume code clear the
port's bit in hub->change_bits. But it seems simpler to just avoid
setting the bit during hub_activate() in the first place. That's what
this patch does.
(Proving that the patch is correct when CONFIG_PM is disabled requires
a little thought. In that setting hub_activate() will be called only
for initialization and resets, since there won't be any resumes or
reset-resumes. During initialization and hub resets the hub doesn't
have any child devices, and so this code path never gets executed.)
Reported-and-tested-by: Paul Zimmerman <pauldzim@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://marc.info/?t=157949360700001&r=1&w=2
CC: David Heinzelmann <heinzelmann.david@gmail.com>
CC: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2001311037460.1577-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Renesas R-Car H3ULCB + Kingfisher Infotainment Board is either not able
to detect the USB3.0 mass storage devices or is detecting those as
USB2.0 high speed devices.
The explanation given by Renesas is that, due to a HW issue, the XHCI
driver does not wake up after going to sleep on connecting a USB3.0
device.
In order to mitigate that, disable the auto-suspend feature
specifically for SMSC hubs from hub_probe() function, as a quirk.
Renesas Kingfisher Infotainment Board has two USB3.0 ports (CN2) which
are connected via USB5534B 4-port SuperSpeed/Hi-Speed, low-power,
configurable hub controller.
[1] SanDisk USB 3.0 device detected as USB-2.0 before the patch
[ 74.036390] usb 5-1.1: new high-speed USB device number 4 using xhci-hcd
[ 74.061598] usb 5-1.1: New USB device found, idVendor=0781, idProduct=5581, bcdDevice= 1.00
[ 74.069976] usb 5-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 74.077303] usb 5-1.1: Product: Ultra
[ 74.080980] usb 5-1.1: Manufacturer: SanDisk
[ 74.085263] usb 5-1.1: SerialNumber: 4C530001110208116550
[2] SanDisk USB 3.0 device detected as USB-3.0 after the patch
[ 34.565078] usb 6-1.1: new SuperSpeed Gen 1 USB device number 3 using xhci-hcd
[ 34.588719] usb 6-1.1: New USB device found, idVendor=0781, idProduct=5581, bcdDevice= 1.00
[ 34.597098] usb 6-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 34.604430] usb 6-1.1: Product: Ultra
[ 34.608110] usb 6-1.1: Manufacturer: SanDisk
[ 34.612397] usb 6-1.1: SerialNumber: 4C530001110208116550
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Hardik Gajjar <hgajjar@de.adit-jv.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1580989763-32291-1-git-send-email-hgajjar@de.adit-jv.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull USB/Thunderbolt/PHY driver updates from Greg KH:
"Here is the big USB and Thunderbolt and PHY driver updates for
5.6-rc1.
With the advent of USB4, "Thunderbolt" has really become USB4, so the
renaming of the Kconfig option and starting to share subsystem code
has begun, hence both subsystems coming in through the same tree here.
PHY driver updates also touched USB drivers, so that is coming in
through here as well.
Major stuff included in here are:
- USB 4 initial support added (i.e. Thunderbolt)
- musb driver updates
- USB gadget driver updates
- PHY driver updates
- USB PHY driver updates
- lots of USB serial stuff fixed up
- USB typec updates
- USB-IP fixes
- lots of other smaller USB driver updates
All of these have been in linux-next for a while now (the usb-serial
tree is already tested in linux-next on its own before merged into
here), with no reported issues"
[ Removed an incorrect compile test enablement for PHY_EXYNOS5250_SATA
that causes configuration warnings - Linus ]
* tag 'usb-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (207 commits)
Doc: ABI: add usb charger uevent
usb: phy: show USB charger type for user
usb: cdns3: fix spelling mistake and rework grammar in text
usb: phy: phy-gpio-vbus-usb: Convert to GPIO descriptors
USB: serial: cyberjack: fix spelling mistake "To" -> "Too"
USB: serial: ir-usb: simplify endpoint check
USB: serial: ir-usb: make set_termios synchronous
USB: serial: ir-usb: fix IrLAP framing
USB: serial: ir-usb: fix link-speed handling
USB: serial: ir-usb: add missing endpoint sanity check
usb: typec: fusb302: fix "op-sink-microwatt" default that was in mW
usb: typec: wcove: fix "op-sink-microwatt" default that was in mW
usb: dwc3: pci: add ID for the Intel Comet Lake -V variant
usb: typec: tcpci: mask event interrupts when remove driver
usb: host: xhci-tegra: set MODULE_FIRMWARE for tegra186
usb: chipidea: add inline for ci_hdrc_host_driver_init if host is not defined
usb: chipidea: handle single role for usb role class
usb: musb: fix spelling mistake: "periperal" -> "peripheral"
phy: ti: j721e-wiz: Fix build error without CONFIG_OF_ADDRESS
USB: usbfs: Always unlink URBs in reverse order
...
Pull ioremap updates from Christoph Hellwig:
"Remove the ioremap_nocache API (plus wrappers) that are always
identical to ioremap"
* tag 'ioremap-5.6' of git://git.infradead.org/users/hch/ioremap:
remove ioremap_nocache and devm_ioremap_nocache
MIPS: define ioremap_nocache to ioremap
When the kernel unlinks a bunch of URBs for a single endpoint, it
should always unlink them in reverse order. This eliminates any
possibility that some URB x will be unlinked before it can execute but
the following URB x+1 will execute before it can be unlinked. Such an
event would be bad, for obvious reasons.
Chris Dickens pointed out that usbfs doesn't behave this way when it
is unbound from an interface. All pending URBs are cancelled, but in
the order of submission. This patch changes the behavior to make the
unlinks occur in reverse order. It similarly changes the behavior
when usbfs cancels the continuation URBs for a BULK endpoint.
Suggested-by: Chris Dickens <christopher.a.dickens@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2001171045380.1571-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If hub_activate() is called before D+ has stabilized after remote
wakeup, the following situation might occur:
__ ___________________
/ \ /
D+ __/ \__/
Hub _______________________________
| ^ ^ ^
| | | |
Host _____v__|___|___________|______
| | | |
| | | \-- Interrupt Transfer (*3)
| | \-- ClearPortFeature (*2)
| \-- GetPortStatus (*1)
\-- Host detects remote wakeup
- D+ goes high, Host starts running by remote wakeup
- D+ is not stable, goes low
- Host requests GetPortStatus at (*1) and gets the following hub status:
- Current Connect Status bit is 0
- Connect Status Change bit is 1
- D+ stabilizes, goes high
- Host requests ClearPortFeature and thus Connect Status Change bit is
cleared at (*2)
- After waiting 100 ms, Host starts the Interrupt Transfer at (*3)
- Since the Connect Status Change bit is 0, Hub returns NAK.
In this case, port_event() is not called in hub_event() and Host cannot
recognize device. To solve this issue, flag change_bits even if only
Connect Status Change bit is 1 when got in the first GetPortStatus.
This issue occurs rarely because it only if D+ changes during a very
short time between GetPortStatus and ClearPortFeature. However, it is
fatal if it occurs in embedded system.
Signed-off-by: Keiya Nobuta <nobuta.keiya@fujitsu.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200109051448.28150-1-nobuta.keiya@fujitsu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It turns out that even though endpoints with a maxpacket length of 0
aren't useful for data transfer, the descriptors do serve other
purposes. In particular, skipping them will also skip over other
class-specific descriptors for classes such as UVC. This unexpected
side effect has caused some UVC cameras to stop working.
In addition, the USB spec requires that when isochronous endpoint
descriptors are present in an interface's altsetting 0 (which is true
on some devices), the maxpacket size _must_ be set to 0. Warning
about such things seems like a bad idea.
This patch updates an earlier commit which would log a warning and
skip these endpoint descriptors. Now we only log a warning, and we
don't even do that for isochronous endpoints in altsetting 0.
We don't need to worry about preventing endpoints with maxpacket = 0
from ever being used for data transfers; usb_submit_urb() already
checks for this.
Reported-and-tested-by: Roger Whittaker <Roger.Whittaker@suse.com>
Fixes: d482c7bb05 ("USB: Skip endpoints with 0 maxpacket length")
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://marc.info/?l=linux-usb&m=157790377329882&w=2
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2001061040270.1514-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Amend the endpoint-descriptor sanity checks to detect all duplicate
endpoint addresses in a configuration.
Commit 0a8fd13462 ("USB: fix problems with duplicate endpoint
addresses") added a check for duplicate endpoint addresses within a
single alternate setting, but did not look for duplicate addresses in
other interfaces.
The current check would also not detect all duplicate addresses when one
endpoint is as a (bi-directional) control endpoint.
This specifically avoids overwriting the endpoint entries in struct
usb_device when enabling a duplicate endpoint, something which could
potentially lead to crashes or leaks, for example, when endpoints are
later disabled.
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20191219161016.6695-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix commit 7b81cb6bdd ("usb: add a HCD_DMA flag instead of
guestimating DMA capabilities") where local memory USB drivers
erroneously allocate DMA memory instead of pool memory, causing
OHCI Unrecoverable Error, disabled
HC died; cleaning up
The order between hcd_uses_dma() and hcd->localmem_pool is now
arranged as in hcd_buffer_alloc() and hcd_buffer_free(), with the
test for hcd->localmem_pool placed first.
As an alternative, one might consider adjusting hcd_uses_dma() with
static inline bool hcd_uses_dma(struct usb_hcd *hcd)
{
- return IS_ENABLED(CONFIG_HAS_DMA) && (hcd->driver->flags & HCD_DMA);
+ return IS_ENABLED(CONFIG_HAS_DMA) &&
+ (hcd->driver->flags & HCD_DMA) &&
+ (hcd->localmem_pool == NULL);
}
One can also consider unsetting HCD_DMA for local memory pool drivers.
Fixes: 7b81cb6bdd ("usb: add a HCD_DMA flag instead of guestimating DMA capabilities")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Fredrik Noring <noring@nocrew.org>
Link: https://lore.kernel.org/r/20191210172905.GA52526@sx9
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull removal of most of fs/compat_ioctl.c from Arnd Bergmann:
"As part of the cleanup of some remaining y2038 issues, I came to
fs/compat_ioctl.c, which still has a couple of commands that need
support for time64_t.
In completely unrelated work, I spent time on cleaning up parts of
this file in the past, moving things out into drivers instead.
After Al Viro reviewed an earlier version of this series and did a lot
more of that cleanup, I decided to try to completely eliminate the
rest of it and move it all into drivers.
This series incorporates some of Al's work and many patches of my own,
but in the end stops short of actually removing the last part, which
is the scsi ioctl handlers. I have patches for those as well, but they
need more testing or possibly a rewrite"
* tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (42 commits)
scsi: sd: enable compat ioctls for sed-opal
pktcdvd: add compat_ioctl handler
compat_ioctl: move SG_GET_REQUEST_TABLE handling
compat_ioctl: ppp: move simple commands into ppp_generic.c
compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t
compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic
compat_ioctl: unify copy-in of ppp filters
tty: handle compat PPP ioctls
compat_ioctl: move SIOCOUTQ out of compat_ioctl.c
compat_ioctl: handle SIOCOUTQNSD
af_unix: add compat_ioctl support
compat_ioctl: reimplement SG_IO handling
compat_ioctl: move WDIOC handling into wdt drivers
fs: compat_ioctl: move FITRIM emulation into file systems
gfs2: add compat_ioctl support
compat_ioctl: remove unused convert_in_user macro
compat_ioctl: remove last RAID handling code
compat_ioctl: remove /dev/raw ioctl translation
compat_ioctl: remove PCI ioctl translation
compat_ioctl: remove joystick ioctl translation
...
Pull dma-mapping updates from Christoph Hellwig:
- improve dma-debug scalability (Eric Dumazet)
- tiny dma-debug cleanup (Dan Carpenter)
- check for vmap memory in dma_map_single (Kees Cook)
- check for dma_addr_t overflows in dma-direct when using DMA offsets
(Nicolas Saenz Julienne)
- switch the x86 sta2x11 SOC to use more generic DMA code (Nicolas
Saenz Julienne)
- fix arm-nommu dma-ranges handling (Vladimir Murzin)
- use __initdata in CMA (Shyam Saini)
- replace the bus dma mask with a limit (Nicolas Saenz Julienne)
- merge the remapping helpers into the main dma-direct flow (me)
- switch xtensa to the generic dma remap handling (me)
- various cleanups around dma_capable (me)
- remove unused dev arguments to various dma-noncoherent helpers (me)
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux:
* tag 'dma-mapping-5.5' of git://git.infradead.org/users/hch/dma-mapping: (22 commits)
dma-mapping: treat dev->bus_dma_mask as a DMA limit
dma-direct: exclude dma_direct_map_resource from the min_low_pfn check
dma-direct: don't check swiotlb=force in dma_direct_map_resource
dma-debug: clean up put_hash_bucket()
powerpc: remove support for NULL dev in __phys_to_dma / __dma_to_phys
dma-direct: avoid a forward declaration for phys_to_dma
dma-direct: unify the dma_capable definitions
dma-mapping: drop the dev argument to arch_sync_dma_for_*
x86/PCI: sta2x11: use default DMA address translation
dma-direct: check for overflows on 32 bit DMA addresses
dma-debug: increase HASH_SIZE
dma-debug: reorder struct dma_debug_entry fields
xtensa: use the generic uncached segment support
dma-mapping: merge the generic remapping helpers into dma-direct
dma-direct: provide mmap and get_sgtable method overrides
dma-direct: remove the dma_handle argument to __dma_direct_alloc_pages
dma-direct: remove __dma_direct_free_pages
usb: core: Remove redundant vmap checks
kernel: dma-contiguous: mark CMA parameters __initdata/__initconst
dma-debug: add a schedule point in debug_dma_dump_mappings()
...
On Dell WD15 dock, sometimes USB ethernet cannot be detected after plugging
cable to the ethernet port, the hub and roothub get runtime resumed and
runtime suspended immediately:
...
[ 433.315169] xhci_hcd 0000:3a:00.0: hcd_pci_runtime_resume: 0
[ 433.315204] usb usb4: usb auto-resume
[ 433.315226] hub 4-0:1.0: hub_resume
[ 433.315239] xhci_hcd 0000:3a:00.0: Get port status 4-1 read: 0x10202e2, return 0x10343
[ 433.315264] usb usb4-port1: status 0343 change 0001
[ 433.315279] xhci_hcd 0000:3a:00.0: clear port1 connect change, portsc: 0x10002e2
[ 433.315293] xhci_hcd 0000:3a:00.0: Get port status 4-2 read: 0x2a0, return 0x2a0
[ 433.317012] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[ 433.422282] xhci_hcd 0000:3a:00.0: Get port status 4-1 read: 0x10002e2, return 0x343
[ 433.422307] usb usb4-port1: do warm reset
[ 433.422311] usb 4-1: device reset not allowed in state 8
[ 433.422339] hub 4-0:1.0: state 7 ports 2 chg 0002 evt 0000
[ 433.422346] xhci_hcd 0000:3a:00.0: Get port status 4-1 read: 0x10002e2, return 0x343
[ 433.422356] usb usb4-port1: do warm reset
[ 433.422358] usb 4-1: device reset not allowed in state 8
[ 433.422428] xhci_hcd 0000:3a:00.0: set port remote wake mask, actual port 0 status = 0xf0002e2
[ 433.422455] xhci_hcd 0000:3a:00.0: set port remote wake mask, actual port 1 status = 0xe0002a0
[ 433.422465] hub 4-0:1.0: hub_suspend
[ 433.422475] usb usb4: bus auto-suspend, wakeup 1
[ 433.426161] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[ 433.466209] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.510204] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.554051] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.598235] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.642154] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.686204] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.730205] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.774203] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.818207] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.862040] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[ 433.862053] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[ 433.862077] xhci_hcd 0000:3a:00.0: xhci_suspend: stopping port polling.
[ 433.862096] xhci_hcd 0000:3a:00.0: // Setting command ring address to 0x8578fc001
[ 433.862312] xhci_hcd 0000:3a:00.0: hcd_pci_runtime_suspend: 0
[ 433.862445] xhci_hcd 0000:3a:00.0: PME# enabled
[ 433.902376] xhci_hcd 0000:3a:00.0: restoring config space at offset 0xc (was 0x0, writing 0x20)
[ 433.902395] xhci_hcd 0000:3a:00.0: restoring config space at offset 0x4 (was 0x100000, writing 0x100403)
[ 433.902490] xhci_hcd 0000:3a:00.0: PME# disabled
[ 433.902504] xhci_hcd 0000:3a:00.0: enabling bus mastering
[ 433.902547] xhci_hcd 0000:3a:00.0: // Setting command ring address to 0x8578fc001
[ 433.902649] pcieport 0000:00:1b.0: PME: Spurious native interrupt!
[ 433.902839] xhci_hcd 0000:3a:00.0: Port change event, 4-1, id 3, portsc: 0xb0202e2
[ 433.902842] xhci_hcd 0000:3a:00.0: resume root hub
[ 433.902845] xhci_hcd 0000:3a:00.0: handle_port_status: starting port polling.
[ 433.902877] xhci_hcd 0000:3a:00.0: xhci_resume: starting port polling.
[ 433.902889] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[ 433.902891] xhci_hcd 0000:3a:00.0: hcd_pci_runtime_resume: 0
[ 433.902919] usb usb4: usb wakeup-resume
[ 433.902942] usb usb4: usb auto-resume
[ 433.902966] hub 4-0:1.0: hub_resume
...
As Mathias pointed out, the hub enters Cold Attach Status state and
requires a warm reset. However usb_reset_device() bails out early when
the device is in suspended state, as its callers port_event() and
hub_event() don't always resume the device.
Since there's nothing wrong to reset a suspended device, allow
usb_reset_device() to do so to solve the issue.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191106062710.29880-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that the vmap area checks are being performed in the DMA
infrastructure directly, there is no need to repeat them in USB.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Endpoints with a maxpacket length of 0 are probably useless. They
can't transfer any data, and it's not at all unlikely that an HCD will
crash or hang when trying to handle an URB for such an endpoint.
Currently the USB core does not check for endpoints having a maxpacket
value of 0. This patch adds a check, printing a warning and skipping
over any endpoints it catches.
Now, the USB spec does not rule out endpoints having maxpacket = 0.
But since they wouldn't have any practical use, there doesn't seem to
be any good reason for us to accept them.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1910281050420.1485-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
