Even in source code of this driver there is an author's description:
/*
* Even if we have an I2C bus, we can't assume that the cable
* is disconnected if drm_probe_ddc fails. Some cables don't
* wire the DDC pins, or the I2C bus might not be working at
* all.
*/
That's true. DDC and VGA channels are independent, and therefore
we cannot decide whether the monitor is connected or not,
depending on the information from the DDC.
So the monitor should always be considered connected.
Thus there is no reason to use connector detect callback for this
driver: DRM sub-system considers monitor always connected if there
is no detect() callback registered with drm_connector_init().
How to reproduce the bug:
* setup: i.MX8QXP, LCDIF video module + gpu/drm/mxsfb driver,
adv712x VGA DAC + dumb-vga-dac driver, VGA-connector w/o DDC;
* try to use drivers chain mxsfb-drm + dumb-vga-dac;
* any DRM applications consider the monitor is not connected:
===========
$ weston-start
$ cat /var/log/weston.log
...
DRM: head 'VGA-1' found, connector 32 is disconnected.
...
$ cat /sys/devices/platform/5a180000.lcdif/drm/card0/card0-VGA-1/status
unknown
===========
Oleksandr Suvorov (1):
drm/bridge: vga-dac: Fix detect of monitor connection
drivers/gpu/drm/bridge/dumb-vga-dac.c | 18 ------------------
1 file changed, 18 deletions(-)
--
2.20.1
Hello Greg,
Can you please consider including the following patches in the stable
linux-4.14.y branch?
An NFS server accepts only a limited number of concurrent v4.1+ mounts. Once
that limit is reached, on the affected client side, mount.nfs appears to hang to
keep reissuing CREATE_SESSION calls until one of them succeeds. This is to bump
the limit, also return smaller ca_maxrequests as the limit approaches instead of
waiting till we have to fail CREATE_SESSION completely.
44d8660d3bb0("nfsd: increase DRC cache limit")
de766e570413("nfsd: give out fewer session slots as limit approaches")
c54f24e338ed("nfsd: fix performance-limiting session calculation")
Thanks,
Qian Lu