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df3aa13c7b
This reverts commita81cf9799a. The patch causes a regression, which I cannot find the reason for. So let's revert for now, as a revert hurts only performance. Original report: I was trying to resolve the problem with Oliver but we don't get any conclusion for 5 months, so I am now sending this to mail list and cdc_acm authors. I am using simple request-response protocol to obtain the boiller parameters in constant intervals. A simple one transaction is: 1. opening the /dev/ttyACM0 2. sending the following 10-bytes request to the device: unsigned char req[] = {0x02, 0xfe, 0x01, 0x05, 0x08, 0x02, 0x01, 0x69, 0xab, 0x03}; 3. reading response (frame of 74 bytes length). 4. closing the descriptor I am doing this transaction with 5 seconds intervals. Before the bad commit everything was working correctly: I've got a requests and a responses in a timely manner. After the bad commit more time I am using the kernel module, more problems I have. The graph [2] is showing the problem. As you can see after module load all seems fine but after about 30 minutes I've got a plenty of EAGAINs when doing read()'s and trying to read back the data. When I rmmod and insmod the cdc_acm module again, then the situation is starting over again: running ok shortly after load, and more time it is running, more EAGAINs I have when calling read(). As a bonus I can see the problem on the device itself: The device is configured as you can see here on this screen [3]. It has two transmision LEDs: TX and RX. Blink duration is set for 100ms. This is a recording before the bad commit when all is working fine: [4] And this is with the bad commit: [5] As you can see the TX led is blinking wrongly long (indicating transmission?) and I have problems doing read() calls (EAGAIN). Reported-by: Mariusz Bialonczyk <manio@skyboo.net> Signed-off-by: Oliver Neukum <oneukum@suse.com> Fixes:a81cf9799a("cdc-acm: implement put_char() and flush_chars()") Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
142 lines
3.9 KiB
C
142 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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*
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* Includes for cdc-acm.c
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*
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* Mainly take from usbnet's cdc-ether part
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*
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*/
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/*
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* CMSPAR, some architectures can't have space and mark parity.
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*/
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#ifndef CMSPAR
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#define CMSPAR 0
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#endif
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/*
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* Major and minor numbers.
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*/
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#define ACM_TTY_MAJOR 166
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#define ACM_TTY_MINORS 256
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/*
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* Requests.
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*/
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#define USB_RT_ACM (USB_TYPE_CLASS | USB_RECIP_INTERFACE)
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/*
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* Output control lines.
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*/
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#define ACM_CTRL_DTR 0x01
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#define ACM_CTRL_RTS 0x02
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/*
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* Input control lines and line errors.
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*/
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#define ACM_CTRL_DCD 0x01
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#define ACM_CTRL_DSR 0x02
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#define ACM_CTRL_BRK 0x04
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#define ACM_CTRL_RI 0x08
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#define ACM_CTRL_FRAMING 0x10
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#define ACM_CTRL_PARITY 0x20
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#define ACM_CTRL_OVERRUN 0x40
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/*
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* Internal driver structures.
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*/
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/*
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* The only reason to have several buffers is to accommodate assumptions
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* in line disciplines. They ask for empty space amount, receive our URB size,
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* and proceed to issue several 1-character writes, assuming they will fit.
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* The very first write takes a complete URB. Fortunately, this only happens
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* when processing onlcr, so we only need 2 buffers. These values must be
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* powers of 2.
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*/
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#define ACM_NW 16
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#define ACM_NR 16
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struct acm_wb {
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unsigned char *buf;
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dma_addr_t dmah;
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int len;
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int use;
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struct urb *urb;
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struct acm *instance;
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};
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struct acm_rb {
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int size;
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unsigned char *base;
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dma_addr_t dma;
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int index;
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struct acm *instance;
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};
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struct acm {
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struct usb_device *dev; /* the corresponding usb device */
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struct usb_interface *control; /* control interface */
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struct usb_interface *data; /* data interface */
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unsigned in, out; /* i/o pipes */
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struct tty_port port; /* our tty port data */
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struct urb *ctrlurb; /* urbs */
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u8 *ctrl_buffer; /* buffers of urbs */
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dma_addr_t ctrl_dma; /* dma handles of buffers */
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u8 *country_codes; /* country codes from device */
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unsigned int country_code_size; /* size of this buffer */
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unsigned int country_rel_date; /* release date of version */
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struct acm_wb wb[ACM_NW];
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unsigned long read_urbs_free;
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struct urb *read_urbs[ACM_NR];
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struct acm_rb read_buffers[ACM_NR];
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int rx_buflimit;
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spinlock_t read_lock;
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u8 *notification_buffer; /* to reassemble fragmented notifications */
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unsigned int nb_index;
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unsigned int nb_size;
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int transmitting;
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spinlock_t write_lock;
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struct mutex mutex;
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bool disconnected;
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unsigned long flags;
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# define EVENT_TTY_WAKEUP 0
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# define EVENT_RX_STALL 1
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struct usb_cdc_line_coding line; /* bits, stop, parity */
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struct work_struct work; /* work queue entry for line discipline waking up */
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unsigned int ctrlin; /* input control lines (DCD, DSR, RI, break, overruns) */
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unsigned int ctrlout; /* output control lines (DTR, RTS) */
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struct async_icount iocount; /* counters for control line changes */
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struct async_icount oldcount; /* for comparison of counter */
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wait_queue_head_t wioctl; /* for ioctl */
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unsigned int writesize; /* max packet size for the output bulk endpoint */
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unsigned int readsize,ctrlsize; /* buffer sizes for freeing */
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unsigned int minor; /* acm minor number */
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unsigned char clocal; /* termios CLOCAL */
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unsigned int ctrl_caps; /* control capabilities from the class specific header */
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unsigned int susp_count; /* number of suspended interfaces */
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unsigned int combined_interfaces:1; /* control and data collapsed */
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unsigned int throttled:1; /* actually throttled */
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unsigned int throttle_req:1; /* throttle requested */
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u8 bInterval;
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struct usb_anchor delayed; /* writes queued for a device about to be woken */
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unsigned long quirks;
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};
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#define CDC_DATA_INTERFACE_TYPE 0x0a
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/* constants describing various quirks and errors */
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#define NO_UNION_NORMAL BIT(0)
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#define SINGLE_RX_URB BIT(1)
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#define NO_CAP_LINE BIT(2)
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#define NO_DATA_INTERFACE BIT(4)
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#define IGNORE_DEVICE BIT(5)
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#define QUIRK_CONTROL_LINE_STATE BIT(6)
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#define CLEAR_HALT_CONDITIONS BIT(7)
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#define SEND_ZERO_PACKET BIT(8)
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