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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Macpaul Lin <macpaul.lin@mediatek.com>,
	Johan Hovold <johan@kernel.org>, Oliver Neukum <oneukum@suse.com>
Subject: [PATCH 3.18 26/47] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader.
Date: Fri, 11 Jan 2019 15:08:11 +0100
Message-ID: <20190111130959.422855289@linuxfoundation.org> (raw)
In-Reply-To: <20190111130956.170952125@linuxfoundation.org>

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Macpaul Lin <macpaul.lin@mediatek.com>

commit eafb27fa5283599ce6c5492ea18cf636a28222bb upstream.

Mediatek Preloader is a proprietary embedded boot loader for loading
Little Kernel and Linux into device DRAM.

This boot loader also handle firmware update. Mediatek Preloader will be
enumerated as a virtual COM port when the device is connected to Windows
or Linux OS via CDC-ACM class driver. When the USB enumeration has been
done, Mediatek Preloader will send out handshake command "READY" to PC
actively instead of waiting command from the download tool.

Since Linux 4.12, the commit "tty: reset termios state on device
registration" (93857edd9829e144acb6c7e72d593f6e01aead66) causes Mediatek
Preloader receiving some abnoraml command like "READYXX" as it sent.
This will be recognized as an incorrect response. The behavior change
also causes the download handshake fail. This change only affects
subsequent connects if the reconnected device happens to get the same minor
number.

By disabling the ECHO termios flag could avoid this problem. However, it
cannot be done by user space configuration when download tool open
/dev/ttyACM0. This is because the device running Mediatek Preloader will
send handshake command "READY" immediately once the CDC-ACM driver is
ready.

This patch wants to fix above problem by introducing "DISABLE_ECHO"
property in driver_info. When Mediatek Preloader is connected, the
CDC-ACM driver could disable ECHO flag in termios to avoid the problem.

Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Cc: stable@vger.kernel.org
Reviewed-by: Johan Hovold <johan@kernel.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/class/cdc-acm.c |   10 ++++++++++
 drivers/usb/class/cdc-acm.h |    1 +
 2 files changed, 11 insertions(+)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -502,6 +502,13 @@ static int acm_tty_install(struct tty_dr
 	if (retval)
 		goto error_init_termios;
 
+	/*
+	 * Suppress initial echoing for some devices which might send data
+	 * immediately after acm driver has been installed.
+	 */
+	if (acm->quirks & DISABLE_ECHO)
+		tty->termios.c_lflag &= ~ECHO;
+
 	tty->driver_data = acm;
 
 	return 0;
@@ -1694,6 +1701,9 @@ static const struct usb_device_id acm_id
 	{ USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */
 	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
 	},
+	{ USB_DEVICE(0x0e8d, 0x2000), /* MediaTek Inc Preloader */
+	.driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */
+	},
 	{ USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */
 	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
 	},
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -135,3 +135,4 @@ struct acm {
 #define QUIRK_CONTROL_LINE_STATE	BIT(6)
 #define CLEAR_HALT_CONDITIONS		BIT(7)
 #define SEND_ZERO_PACKET		BIT(8)
+#define DISABLE_ECHO			BIT(9)



  parent reply index

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-11 14:07 [PATCH 3.18 00/47] 3.18.132-stable review Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 01/47] USB: hso: Fix OOB memory access in hso_probe/hso_get_config_data Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 02/47] USB: serial: option: add HP lt4132 Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 03/47] mmc: core: Reset HPI enabled state during re-init and in case of errors Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 04/47] mmc: omap_hsmmc: fix DMA API warning Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 05/47] gpio: max7301: fix driver for use with CONFIG_VMAP_STACK Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 06/47] Drivers: hv: vmbus: Return -EINVAL for the sys files for unopened channels Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 07/47] x86/mtrr: Dont copy uninitialized gentry fields back to userspace Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 08/47] ax25: fix a use-after-free in ax25_fillin_cb() Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 09/47] ibmveth: fix DMA unmap error in ibmveth_xmit_start error path Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 10/47] ipv6: explicitly initialize udp6_addr in udp_sock_create6() Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 11/47] isdn: fix kernel-infoleak in capi_unlocked_ioctl Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 12/47] netrom: fix locking in nr_find_socket() Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 13/47] packet: validate address length Greg Kroah-Hartman
2019-01-11 14:07 ` [PATCH 3.18 14/47] packet: validate address length if non-zero Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 15/47] sctp: initialize sin6_flowinfo for ipv6 addrs in sctp_inet6addr_event Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 16/47] vhost: make sure used idx is seen before log in vhost_add_used_n() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 17/47] VSOCK: Send reset control packet when socket is partially bound Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 18/47] xen/netfront: tolerate frags with no data Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 19/47] sock: Make sock->sk_stamp thread-safe Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 20/47] USB: serial: pl2303: add ids for Hewlett-Packard HP POS pole displays Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 21/47] usb: r8a66597: Fix a possible concurrency use-after-free bug in r8a66597_endpoint_disable() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 22/47] KVM: x86: Use jmp to invoke kvm_spurious_fault() from .fixup Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 23/47] ext4: fix possible use after free in ext4_quota_enable Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 24/47] ext4: missing unlock/put_page() in ext4_try_to_write_inline_data() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 25/47] ext4: force inode writes when nfsd calls commit_metadata() Greg Kroah-Hartman
2019-01-11 14:08 ` Greg Kroah-Hartman [this message]
2019-01-11 14:08 ` [PATCH 3.18 27/47] media: vivid: free bitmap_cap when updating std/timings/etc Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 28/47] MIPS: Ensure pmd_present() returns false after pmd_mknotpresent() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 29/47] MIPS: Align kernel load address to 64KB Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 30/47] CIFS: Fix error mapping for SMB2_LOCK command which caused OFD lock problem Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 31/47] scsi: zfcp: fix posting too many status read buffers leading to adapter shutdown Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 32/47] fork: record start_time late Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 33/47] sunrpc: fix cache_head leak due to queued request Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 34/47] sunrpc: use SVC_NET() in svcauth_gss_* functions Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 35/47] ALSA: cs46xx: Potential NULL dereference in probe Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 36/47] ALSA: usb-audio: Avoid access before bLength check in build_audio_procunit() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 37/47] ALSA: usb-audio: Fix an out-of-bound read in create_composite_quirks Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 38/47] dlm: fixed memory leaks after failed ls_remove_names allocation Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 39/47] dlm: possible memory leak on error path in create_lkb() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 40/47] dlm: lost put_lkb on error path in receive_convert() and receive_unlock() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 41/47] dlm: memory leaks on error path in dlm_user_request() Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 42/47] gfs2: Fix loop in gfs2_rbm_find Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 43/47] b43: Fix error in cordic routine Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 44/47] 9p/net: put a lower bound on msize Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 45/47] ceph: dont update importing caps mseq when handing cap export Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 46/47] genwqe: Fix size check Greg Kroah-Hartman
2019-01-11 14:08 ` [PATCH 3.18 47/47] power: supply: olpc_battery: correct the temperature units Greg Kroah-Hartman
2019-01-11 21:50 ` [PATCH 3.18 00/47] 3.18.132-stable review shuah
2019-01-12 14:58 ` Harsh Shandilya
2019-01-12 17:42 ` Guenter Roeck
2019-01-13  7:44   ` Greg Kroah-Hartman

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