kernel.git/drivers/usb/serial/ch341.c, branch linux-5.14.y

Revert "USB: serial: ch341: fix character loss at high transfer rates"

2021-08-25T07:13:33Z

This reverts commit 3c18e9baee0ef97510dcda78c82285f52626764b. These devices do not appear to send a zero-length packet when the transfer size is a multiple of the bulk-endpoint max-packet size. This means that incoming data may not be processed by the driver until a short packet is received or the receive buffer is full. Revert back to using endpoint-sized receive buffers to avoid stalled reads. Reported-by: Paul Größel Link: https://bugzilla.kernel.org/show_bug.cgi?id=214131 Fixes: 3c18e9baee0e ("USB: serial: ch341: fix character loss at high transfer rates") Cc: stable@vger.kernel.org Cc: Willy Tarreau Link: https://lore.kernel.org/r/20210824121926.19311-1-johan@kernel.org Signed-off-by: Johan Hovold

USB: serial: ch341: fix character loss at high transfer rates

2021-07-29T11:52:10Z

The chip supports high transfer rates, but with the small default buffers (64 bytes read), some entire blocks are regularly lost. This typically happens at 1.5 Mbps (which is the default speed on Rockchip devices) when used as a console to access U-Boot where the output of the "help" command misses many lines and where "printenv" mangles the environment. The FTDI driver doesn't suffer at all from this. One difference is that it uses 512 bytes rx buffers and 256 bytes tx buffers. Adopting these values completely resolved the issue, even the output of "dmesg" is reliable. I preferred to leave the Tx value unchanged as it is not involved in this issue, while a change could increase the risk of triggering the same issue with other devices having too small buffers. I verified that it backports well (and works) at least to 5.4. It's of low importance enough to be dropped where it doesn't trivially apply anymore. Cc: stable@vger.kernel.org Signed-off-by: Willy Tarreau Link: https://lore.kernel.org/r/20210724152739.18726-1-w@1wt.eu Signed-off-by: Johan Hovold

USB: serial: ch341: add new Product ID

2021-03-09T08:05:36Z

Add PID for CH340 that's found on cheap programmers. The driver works flawlessly as soon as the new PID (0x9986) is added to it. These look like ANU232MI but ship with a ch341 inside. They have no special identifiers (mine only has the string "DB9D20130716" printed on the PCB and nothing identifiable on the packaging. The merchant i bought it from doesn't sell these anymore). the lsusb -v output is: Bus 001 Device 009: ID 9986:7523 Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 8 idVendor 0x9986 idProduct 0x7523 bcdDevice 2.54 iManufacturer 0 iProduct 0 iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0027 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 96mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 3 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 1 bInterfaceProtocol 2 iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0008 1x 8 bytes bInterval 1 Signed-off-by: Niv Sardi Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold

USB: serial: make remove callback return void

2021-02-09T12:13:58Z

All usb_serial drivers return 0 in their remove callbacks and driver core ignores the value returned by usb_serial_device_remove(). So change the remove callback to return void and return 0 unconditionally in usb_serial_device_remove(). Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20210208143149.963644-2-uwe@kleine-koenig.org Signed-off-by: Johan Hovold

USB: serial: ch341: sort device-id entries

2020-12-03T09:28:55Z

Keep the device-id entries sorted to make it easier to add new ones in the right spot. Reviewed-by: Greg Kroah-Hartman Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold

USB: serial: ch341: add new Product ID for CH341A

2020-12-03T09:09:45Z

Add PID for CH340 that's found on a ch341 based Programmer made by keeyees. The specific device that contains the serial converter is described here: http://www.keeyees.com/a/Products/ej/36.html The driver works flawlessly as soon as the new PID (0x5512) is added to it. Signed-off-by: Jan-Niklas Burfeind Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold

Merge tag 'usb-serial-5.9-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next

2020-07-28T15:33:10Z

Johan writes: USB-serial updates for 5.9-rc1 Here are the USB-serial updates for 5.9-rc1, including: - console flow-control support - simulated line-breaks on some ch341 - hardware flow-control fixes for cp210x - break-detection and sysrq fixes for ftdi_sio - sysrq optimisations - input parity checking for cp210x Included are also some new device ids and various clean ups. All have been in linux-next with no reported issues. * tag 'usb-serial-5.9-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial: (31 commits) USB: serial: qcserial: add EM7305 QDL product ID USB: serial: iuu_phoenix: fix led-activity helpers USB: serial: sierra: clean up special-interface handling USB: serial: cp210x: use in-kernel types in port data USB: serial: cp210x: drop unnecessary packed attributes USB: serial: cp210x: add support for TIOCGICOUNT USB: serial: cp210x: add support for line-status events USB: serial: cp210x: disable interface on errors in open USB: serial: drop redundant transfer-buffer casts USB: serial: drop extern keyword from function declarations USB: serial: drop unnecessary sysrq include USB: serial: add sysrq break-handler dummy USB: serial: inline sysrq dummy function USB: serial: only process sysrq when enabled USB: serial: only set sysrq timestamp for consoles USB: serial: ftdi_sio: fix break and sysrq handling USB: serial: ftdi_sio: clean up receive processing USB: serial: ftdi_sio: make process-packet buffer unsigned USB: serial: use fallthrough pseudo-keyword USB: serial: ch341: fix missing simulated-break margin ...

USB: serial: ch341: fix missing simulated-break margin

2020-07-07T15:32:02Z

On devices which do not support break signalling a break condition is simulated by sending a NUL byte at the lowest possible speed. The break condition will be 9 bit periods long (start bit and eight data bits), but the transmission itself also includes the stop bit. Add the missing safety margin of one bit which is intended to account for timing differences, and fix up the corresponding comment. Signed-off-by: Michael Hanselmann Link: https://lore.kernel.org/r/9909b288-294d-16b9-9f14-51eb79c63b6c@msgid.hansmi.ch [ johan: amend commit message ] Signed-off-by: Johan Hovold

USB: serial: ch341: simulate break condition if not supported

2020-07-06T09:25:07Z

A subset of all CH341 devices don't support a real break condition. This fact is already used in the "ch341_detect_quirks" function. With this change a quirk is implemented to simulate a break condition by temporarily lowering the baud rate and sending a NUL byte. The primary drawbacks of this approach are that the duration of the break can't be controlled by userland and that data incoming during a simulated break is corrupted. The "TTY_DRIVER_HARDWARE_BREAK" serial driver flag was investigated as an alternative. It's a driver-wide flag and would've required significant changes to the serial and USB-serial driver frameworks to expose it for individual USB-serial adapters. Tested by sending a break condition and watching the TX pin using an oscilloscope. Signed-off-by: Michael Hanselmann Link: https://lore.kernel.org/r/f34a9b6e-ec2a-0873-e97b-2d5b2170e2ff@msgid.hansmi.ch [ johan: condense info message ] Signed-off-by: Johan Hovold

USB: serial: ch341: add min and max line-speed macros

2020-06-30T10:07:00Z

The line-speed algorithm clamps the requested value to the supported range instead of bailing out on unsupported values. Provide min and max macros and indicate how they are derived instead of hardcoding the limits. Note that the algorithm depends on the minimum rate (45.78 bps) being rounded up (and the maximum rate being rounded down) to avoid special casing. Suggested-by: Michael Hanselmann Link: https://lore.kernel.org/r/20200630095756.GZ3334@localhost Signed-off-by: Johan Hovold