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dm: virtio-input: ignore MSC_TIMESTAMP from guest 

(EV_MSC, MSC_TIMESTAMP) is added to each frame just before the
SYN event since kernel 4.15. EV_MSC is configured as
INPUT_PASS_TO_ALL. In the use case of virtio-input, there is
a loop as follows:
- A mt frame with (EV_MSC, MSC_TIMESTAMP) is passed to FE.
- FE will call virtinput_status to pass (EV_MSC, MSC_TIMESTAMP)
  back to BE.
- BE writes this event to evdev. Because (EV_MSC, MSC_TIMESTAMP)
  is configured as INPUT_PASS_TO_ALL, it will be written into
  the event buffer of evdev then be read out by BE without
  SYN followed.
- Each mt frame will introduce one (EV_MSC, MSC_TIMESTAMP).
  Later the frame becomes larger and larger...

This patch fixed above issue by ignoring MSC_TIMESTAMP from guest.
Besides that timestamp is added for every status event from guest
before writing to evdev.

Tracked-On: #1670
Signed-off-by: Jian Jun Chen <jian.jun.chen@intel.com>
Acked-by: Yu Wang <yu1.wang@intel.com>
This commit is contained in:
Jian Jun Chen 2018-11-01 15:26:34 +08:00 committed by lijinxia
parent ed113f570f
commit 94dadc1d14
1 changed files with 44 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
devicemodel/hw/pci/virtio/virtio_input.c
View File

@ -208,6 +208,33 @@ virtio_input_cfgwrite(void *vdev, int offset, int size, uint32_t val)
return 0;
}
static bool
virtio_input_ignore_event(struct virtio_input_event *event)
{
if (!event)
return true;
/* kernel commit 29cc309d8bf19a36c5196bf626662319af6e3c0b
* (HID: hid-multitouch: forward MSC_TIMESTAMP)
* since kernel 4.15
* (EV_MSC, MSC_TIMESTAMP) is added to each frame just before
* the SYN event. EV_MSC is configured as INPUT_PASS_TO_ALL.
* In the use case of virtio-input, there is a loop as follows:
* - A mt frame with (EV_MSC, MSC_TIMESTAMP) is passed to FE.
* - FE will call virtinput_status to pass (EV_MSC, MSC_TIMESTAMP)
* back to BE.
* - BE writes this event to evdev. Because (EV_MSC, MSC_TIMESTAMP)
* is configured as INPUT_PASS_TO_ALL, it will be written into
* the event buffer of evdev then be read out by BE without
* SYN followed.
* - Each mt frame will introduce one (EV_MSC, MSC_TIMESTAMP).
* Later the frame becomes larger and larger...
*/
if ((event->type == EV_MSC) && (event->code == MSC_TIMESTAMP))
return true;
return false;
}
static void
virtio_input_notify_event_vq(void *vdev, struct virtio_vq_info *vq)
{
@ -230,14 +257,23 @@ virtio_input_notify_status_vq(void *vdev, struct virtio_vq_info *vq)
n = vq_getchain(vq, &idx, &iov, 1, NULL);
assert(n == 1);
memcpy(&event, iov.iov_base, sizeof(event));
host_event.type = event.type;
host_event.code = event.code;
host_event.value = event.value;
len = write(vi->fd, &host_event, sizeof(host_event));
if (len == -1)
WPRINTF(("%s: write failed, len = %d, errno = %d\n",
__func__, len, errno));
if (vi->fd > 0) {
memcpy(&event, iov.iov_base, sizeof(event));
if (!virtio_input_ignore_event(&event)) {
host_event.type = event.type;
host_event.code = event.code;
host_event.value = event.value;
if (gettimeofday(&host_event.time, NULL)) {
WPRINTF(("vtinput: gettimeofday failed\n"));
break;
}
len = write(vi->fd, &host_event, sizeof(host_event));
if (len == -1)
WPRINTF(("%s: write failed, len = %d, "
"errno = %d\n",
__func__, len, errno));
}
}
vq_relchain(vq, idx, sizeof(event)); /* Release the chain */
}
vq_endchains(vq, 1); /* Generate interrupt if appropriate. */