On Fri, Sep 08, 2017 at 09:46:02AM +0700, Nhan Nguyen wrote: > commit 3587c856675c45809010c2cee5b21096f6e8e938 upstream. > > I've found that by just turning the chip on and off via the > POWER_DOWN register, I end up getting i2c_transfer errors on > HiKey. > > Investigating further, it turns out that some of the register > state in hardware is getting lost, as the device registers are > reset when the chip is powered down. > > Thus this patch simply re-writes the i2c address to the > ADV7511_REG_EDID_I2C_ADDR register to ensure its properly set > before we try to read the EDID data. > > Cc: David Airlie <airlied@xxxxxxxx> > Cc: Archit Taneja <architt@xxxxxxxxxxxxxx> > Cc: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > Cc: Lars-Peter Clausen <lars@xxxxxxxxxx> > Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > Cc: stable@xxxxxxxxxxxxxxx > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Tested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> > Signed-off-by: Archit Taneja <architt@xxxxxxxxxxxxxx> > Signed-off-by: Thong Ho <thong.ho.px@xxxxxxxxxxxxxxx> > Signed-off-by: Nhan Nguyen <nhan.nguyen.yb@xxxxxxxxxxx> > Link: http://patchwork.freedesktop.org/patch/msgid/1484614372-15342-7-git-send-email-john.stultz@xxxxxxxxxx > --- > drivers/gpu/drm/i2c/adv7511.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) Can you provide a working backport for the 4.9-stable kernel as well? Also, please do not send backports for patches that do not also work in newer stable kernels, like 4.9, I backported some of this series there, but I shouldn't have to check for you. thanks, greg k-h