Hi Michale, On Fri, Aug 06, 2021 at 12:37:07PM +0200, Michal Simek wrote: > st 24. 3. 2021 v 4:15 odesílatel Laurent Pinchart napsal: > > On Tue, Mar 23, 2021 at 10:55:01AM +0800, quanyang.wang@xxxxxxxxxxxxx wrote: > > > From: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx> > > > > > > When insmod zynqmp-dpsub.ko after rmmod it, system will hang with the > > > error log as below: > > > > > > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > > > [ 88.391289] [drm] Initialized zynqmp-dpsub 1.0.0 20130509 for fd4a0000.display on minor 0 > > > [ 88.529906] Console: switching to colour frame buffer device 128x48 > > > [ 88.549402] zynqmp-dpsub fd4a0000.display: [drm] fb0: zynqmp-dpsubdrm frame buffer device > > > [ 88.571624] zynqmp-dpsub fd4a0000.display: ZynqMP DisplayPort Subsystem driver probed > > > root@xilinx-zynqmp:~# rmmod zynqmp_dpsub > > > [ 94.023404] Console: switching to colour dummy device 80x25 > > > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > > > <hang here> > > > > > > This is because that in zynqmp_dp_probe it tries to access some DP > > > registers while the DP controller is still in the reset state. When > > > running "rmmod zynqmp_dpsub", zynqmp_dp_reset(dp, true) in > > > zynqmp_dp_phy_exit is called to force the DP controller into the reset > > > state. Then insmod will call zynqmp_dp_probe to program the DP registers, > > > but at this moment the DP controller hasn't been brought out of the reset > > > state yet since the function zynqmp_dp_reset(dp, false) is called later and > > > this will result the system hang. > > > > > > Releasing the reset to DP controller before any read/write operation to it > > > will fix this issue. And for symmetry, move zynqmp_dp_reset() call from > > > zynqmp_dp_phy_exit() to zynqmp_dp_remove(). > > > > > > Signed-off-by: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx> > > > > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > Can someone pick this patch? I have it in my tree with a set of other changes, I intend to send a pull request today. -- Regards, Laurent Pinchart
