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Create a separate helper function to issue reset endpont commands
to clear halted endpoints.
This is useful for cases where a halted endpoint is discovered while
completing another command, and the endpoint halt needs to be cleared
with a endpoint reset first.
No functional changes
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-16-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stop endpoint command fails with "context state error" if the endpoint is
already stopped.
This case was observed when a previous URB cancel had just completed and
rang the doorbell to restart the ring, when a new URB cancel queued a stop
endpoint command.
>From xHC hardware pov the endpoint had not yet started, so the stop
endpoint command failed with context state error.
Right after this the doorbell ring took effect and ring was restarted.
Interrupt handler saw a stop endpoint command completion event with
"context state error" and discovered that the ring was back up in
running state.
flushing the write reduces these cases in stress testing, but does not
completely remove the issue.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-15-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xhci driver relies on link TRBs existing in the correct places in TRB
ring buffers shared with the host controller.
The controller should not modify these link TRBs, but in theory a faulty
xHC could do it.
Add some basic sanity checks to avoid infinite loops in interrupt handler,
or accessing unallocated memory outside a ring segment due to missing or
misplaced link TRBs.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-14-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of re-reading, masking and endianness correcting the same trb
several times to get the trb type from an event, just do it once and
store it in a local variable.
Also pass the trb_type directly to the vendor specific event handler,
avoiding one more similar read.
In addition to the security benefit this also cleans up the code
and helps readability.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-13-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When finishing a TD we walk the endpoint dequeue trb pointer
until it matches the last TRB of the TD.
TDs can contain over 100 TRBs, meaning we call a function 100 times,
do a few comparisons and increase a couple values for each of these calls,
all in interrupt context.
This can all be avoided by adding a pointer to the last TRB segment, and
a number of TRBs in the TD. So instead of walking through each TRB just
set the new dequeue segment, pointer, and number of free TRBs directly.
Getting rid of the while loop also reduces the risk of getting stuck in a
infinite loop in the interrupt handler. Loop relied on valid matching
dequeue and last_trb values to break.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-12-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Check that the slot_id that we dug out from command completion event
TRB, is valid before using it to identify the slot associated with the
command that generated the event.
Signed-off-by: Lalithambika Krishna Kumar <lalithambika.krishnakumar@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-11-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xhci driver links together segments in a ring buffer by turning the last
TRB of a segment into a link TRB, pointing to the beginning of
the next segment.
If the first TRB of every segment for some unknown reason is a link TRB
pointing to the next segment, then prepare_ring() loops indefinitely.
This isn't something the xhci driver would do.
xHC hardware has access to these rings, it sholdn't be writing link
TRBs either, but with broken xHC hardware this could in theory be
possible.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-10-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The one case that used this function can use the
xhci_triad_to_transfer_ring() helper instead.
Avoid having several functions doing basically the same thing.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-9-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Two existing ring helpers, xhci_triad_to_transfer_ring() and
xhci_stream_id_to_ring() have partially similar functionality.
Both have some limitation, especieally with boundary checking.
Add a new xhci_virt_ep_to_ring() helper with proper boundary checking
that can replace parts of one helper, and later will completely
replace the other helper.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-8-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Check that the xhci_virt_dev structure that we dug out based
on a slot_id value from a command completion is valid before
dereferencing it.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In several event handlers we need to find the right endpoint
structure from slot_id and ep_index in the event.
Add a helper for this, check that slot_id and ep_index are valid.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-6-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
several command completion handlers are passed the event trb
as a paramtere even if it't not used.
Remove it.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-5-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of passing slot id and endpoint index to
cleanup_halted_endpoint() pass the endpoint structure pointer
as it's already known.
Avoids again digging out the endpoint structure based on
slot id and endpoint index, and passing them along the
call chain for this purpose only.
Add slot_id to the virt_dev structure so that it
can easily be found from a virt_dev, or its child, the
virt_ep endpoint structure.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
isochronous endpoints do not support streams, meaning that
there is only one ring per endpoint.
Avoid double-fetching the transfer event DMA to get the
ring. Also makes passing the event to skip_isoc_td() uncecessary.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When handling transfer events the event is passed along the handling
callpath and parsed again in several occasions.
The event contains slot_id and endpoint index, from which the driver
endpoint structure can be found. There wasn't however a way to get the
endpoint index or parent usb device from this endpoint structure.
A lot of extra event parsing, and thus some DMA doublefetch cases,
and excess variables and code can be avoided by adding endpoint index
and parent usb virt device pointer to the endpoint structure.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This code should return -ENOMEM if the kmalloc() fails but instead
it returns success.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 0f64478cbc7a ("USB: add USB serial mos7720 driver")
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Use the more modern API here instead of using of_match_device() and
avoid casting away const from the returned pointer by pushing the const
type through to the users. This nicely avoids referencing the match
table when it is undefined with configurations where CONFIG_OF=n and
avoids const issues.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Richard Leitner <richard.leitner@skidata.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210123034428.2841052-5-swboyd@chromium.org
With some USB network adapters, such as DM96xx, the following message
is seen for each maximum size receive packet.
dwc2 ff540000.usb: dwc2_update_urb_state(): trimming xfer length
This happens because the packet size requested by the driver is 1522
bytes, wMaxPacketSize is 64, the dwc2 driver configures the chip to
receive 24*64 = 1536 bytes, and the chip does indeed send more than
1522 bytes of data. Since the event does not indicate an error condition,
the message is just noise. Demote it to debug level.
Fixes: 7359d482eb4d3 ("staging: HCD files for the DWC2 driver")
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20210113112052.17063-4-nsaenzjulienne@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In some situations, the following error messages are reported.
dwc2 ff540000.usb: dwc2_hc_chhltd_intr_dma: Channel 1 - ChHltd set, but reason is unknown
dwc2 ff540000.usb: hcint 0x00000002, intsts 0x04000021
This is sometimes followed by:
dwc2 ff540000.usb: dwc2_update_urb_state_abn(): trimming xfer length
and then:
WARNING: CPU: 0 PID: 0 at kernel/v4.19/drivers/usb/dwc2/hcd.c:2913
dwc2_assign_and_init_hc+0x98c/0x990
The warning suggests that an odd buffer address is to be used for DMA.
After an error is observed, the receive buffer may be full
(urb->actual_length >= urb->length). However, the urb is still left in
the queue unless three errors were observed in a row. When it is queued
again, the dwc2 hcd code translates this into a 1-block transfer.
If urb->actual_length (ie the total expected receive length) is not
DMA-aligned, the buffer pointer programmed into the chip will be
unaligned. This results in the observed warning.
To solve the problem, abort input transactions after an error with
unknown cause if the entire packet was already received. This may be
a bit drastic, but we don't really know why the transfer was aborted
even though the entire packet was received. Aborting the transfer in
this situation is less risky than accepting a potentially corrupted
packet.
With this patch in place, the 'ChHltd set' and 'trimming xfer length'
messages are still observed, but there are no more transfer attempts
with odd buffer addresses.
Fixes: 151d0cbdbe860 ("usb: dwc2: make the scheduler handle excessive NAKs better")
Cc: Boris ARZUR <boris@konbu.org>
Cc: Douglas Anderson <dianders@chromium.org>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20210113112052.17063-3-nsaenzjulienne@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DWC2 documentation states that transfers with zero data length should
set the number of packets to 1 and the transfer length to 0. This is not
currently the case for inbound transfers: the transfer length is set to
the maximum packet length. This can have adverse effects if the chip
actually does transfer data as it is programmed to do. Follow chip
documentation and keep the transfer length set to 0 in that situation.
Fixes: 56f5b1cff22a1 ("staging: Core files for the DWC2 driver")
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20210113112052.17063-2-nsaenzjulienne@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tasklets have long been deprecated as being too heavy on the system
by running in irq context - and this is not a performance critical
path. If a higher priority process wants to run, it must wait for
the tasklet to finish before doing so.
c67x00_do_work() will now run in process context and have further
concurrency (tasklets being serialized among themselves), but this
is done holding the c67x00->lock, so it should be fine. Furthermore,
this patch fixes the usage of the lock in the callback as otherwise
it would need to be irq-safe.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210113031537.79859-1-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix up B0 handling which should leave the baud rate unchanged and
specifically not report back a non-B0 rate when B0 is requested; must
temporarily disable hardware flow control so that RTS can be deasserted;
and should reassert DTR/RTS when moving from B0.
Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Make sure that the modem pins are set up correctly when opening the
port to avoid leaving, for example, DTR and RTS configured as inputs,
which is the device default.
This is specifically needed to be able to control DTR and RTS when
hardware flow control is disabled.
Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Fix the gpio-mode handling so that all the pins are under driver control
(i.e. in gpio mode) when hardware flow control is disabled.
This is specifically needed to be able to control RTS.
Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Shift the line-setting values when defining them rather than in
set_termios() for consistency and improved readability.
Signed-off-by: Johan Hovold <johan@kernel.org>
Make sure to release the control interface at disconnect so that the
driver can be unbound without leaking resources (and later rebound).
Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Make sure that the probed device has an interface 0 to avoid
dereferencing a NULL pointer in case of a malicious device or during
USB-descriptor fuzzing.
Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
xhci-mtk needs XHCI_MTK_HOST quirk functions in add_endpoint() and
drop_endpoint() to handle its own sw bandwidth management.
It stores bandwidth data into an internal table every time
add_endpoint() is called, and drops those in drop_endpoint().
But when bandwidth allocation fails at one endpoint, all earlier
allocation from the same interface could still remain at the table.
This patch moves bandwidth management codes to check_bandwidth() and
reset_bandwidth() path. To do so, this patch also adds those functions
to xhci_driver_overrides and lets mtk-xhci to release all failed
endpoints in reset_bandwidth() path.
Fixes: 08e469de87a2 ("usb: xhci-mtk: supports bandwidth scheduling with multi-TT")
Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
Link: https://lore.kernel.org/r/20210113180444.v6.1.Id0d31b5f3ddf5e734d2ab11161ac5821921b1e1e@changeid
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This should return -ENOMEM instead of 0 if the kmalloc() fails.
Fixes: 3f5429746d91 ("USB: Moschip 7840 USB-Serial Driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Some devices, such as the Winbond Electronics Corp. Virtual Com Port
(Vendor=0416, ProdId=5011), lockup when usb_set_interface() or
usb_clear_halt() are called. This device has only a single
altsetting, so it should not be necessary to call usb_set_interface().
Acked-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Jeremy Figgins <kernel@jeremyfiggins.com>
Link: https://lore.kernel.org/r/YAy9kJhM/rG8EQXC@watson
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Information pid/vid of WSDA-200-USB, Lord corporation company:
vid: 199b
pid: ba30
Signed-off-by: Pho Tran <pho.tran@silabs.com>
[ johan: amend comment with product name ]
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
PTR_ERR(chip->tcpci) has been used as a return value,
it is not necessary to assign it to ret, so remove it.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Junlin Yang <yangjunlin@yulong.com>
Link: https://lore.kernel.org/r/20210124143853.1630-1-angkery@163.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the port partner is PD2, the PDOs of the local port should follow the
format defined in PD2 Spec. Dynamically modify the pre-defined PD3 PDOs
and transform them into PD2 format before sending them to the PD2 port
partner.
Reviewed-by: Guenter Roeck <linux@roeckus.net>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210115163311.391332-1-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the fixes in here and this resolves a merge issue with
drivers/usb/gadget/udc/bdc/Kconfig.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for USB controller present on the AM64x SoC.
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Peter Chen <peter.chen@kernel.org>
This driver includes the legacy GPIO header <linux/gpio.h>,
the new GPIO header <linux/gpio/consumer.h> and
the deprecated OF GPIO header <linux/of_gpio.h> yet
fail to use symbols from any of them, so drop these
includes.
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210120225045.173556-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Port partner could send PR_SWAP/DR_SWAP/VCONN_SWAP/Request just after it
enters Ready states. This will cause conficts if the port is going to
send DISC_IDENT in the Ready states of TCPM. Set a flag indicating that
the state machine is processing VDM and respond Wait messages until the
VDM state machine stops.
Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210114145053.1952756-4-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PD3.0 Spec 6.8.1 describes how to handle Protocol Error. There are
general rules defined in Table 6-61 which regulate incoming Message
handling. If the incoming Message is unexpected, unsupported, or
unrecognized, Protocol Error occurs. Follow the rules to handle these
situations. Also consider PD2.0 connection (PD2.0 Spec Table 6-36) for
backward compatibilities.
To know the types of AMS in all the recipient's states, identify those
AMS who are initiated by the port partner but not yet recorded in the
current code.
Besides, introduce a new state CHUNK_NOT_SUPP to delay the NOT_SUPPORTED
message after receiving a chunked message.
Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210114145053.1952756-3-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch provides the implementation of Collision Avoidance introduced
in PD3.0. The start of each Atomic Message Sequence (AMS) initiated by
the port will be denied if the current AMS is not interruptible. The
Source port will set the CC to SinkTxNG if it is going to initiate an
AMS, and SinkTxOk otherwise. Meanwhile, any AMS initiated by a Sink port
will be denied in TCPM if the port partner (Source) sets SinkTxNG except
for HARD_RESET and SOFT_RESET.
Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210114145053.1952756-2-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Exar XR21V141X can be used in either ACM mode using the cdc-acm
driver or in "custom driver" mode in which further features such as
hardware and software flow control, GPIO control and in-band line-status
reporting are available.
In ACM mode the device always enables RTS/CTS flow control, something
which could prevent transmission in case the CTS input isn't wired up
correctly.
Ensure that cdc_acm will not bind to the device if the custom USB-serial
driver is enabled.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20201122170822.21715-4-mani@kernel.org
[ johan: rewrite commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Add support for MaxLinear/Exar USB to Serial converters. This driver
only supports XR21V141X series but it can be extended to other series
from Exar as well in future.
This driver is inspired from the initial one submitted by Patong Yang:
https://lore.kernel.org/r/20180404070634.nhspvmxcjwfgjkcv@advantechmxl-desktop
While the initial driver was a custom tty USB driver exposing whole
new serial interface ttyXRUSBn, this version is completely based on USB
serial core thus exposing the interfaces as ttyUSBn. This will avoid
the overhead of exposing a new USB serial interface which the userspace
tools are unaware of.
The Exar XR21V141X can be used in either ACM mode using the cdc-acm
driver or in "custom driver" mode in which further features such as
hardware and software flow control, GPIO control and in-band line-status
reporting are available.
In ACM mode the device always enables RTS/CTS flow control, something
which could prevent transmission in case the CTS input isn't wired up
corrently.
A follow-on patch will prevent cdc_acm from binding whenever this driver
is enabled.
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20201122170822.21715-2-mani@kernel.org
[ johan: fix some style nits, group related functions, drop unused
callbacks, and amend commit message; a few remaining
non-trivial issues will be fixed separately ]
Signed-off-by: Johan Hovold <johan@kernel.org>
