diff options
author | Quanyang Wang <quanyang.wang@windriver.com> | 2021-03-23 10:55:01 +0800 |
---|---|---|
committer | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2021-08-09 02:28:04 +0300 |
commit | a338619bd76011035d462f0f9e8b2f24d7fe5a1e (patch) | |
tree | 1078d9ef35eba9f987ae8431229cb22646ff843c | |
parent | 97271c7ee1cfb2c3fcc951e4031ffabb7c33f5b1 (diff) | |
download | linux-a338619bd76011035d462f0f9e8b2f24d7fe5a1e.tar.bz2 |
drm: xlnx: zynqmp: release reset to DP controller before accessing DP registers
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@windriver.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
-rw-r--r-- | drivers/gpu/drm/xlnx/zynqmp_dp.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c index 82430ca9b913..6f588dc09ba6 100644 --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c @@ -402,10 +402,6 @@ static int zynqmp_dp_phy_init(struct zynqmp_dp *dp) } } - ret = zynqmp_dp_reset(dp, false); - if (ret < 0) - return ret; - zynqmp_dp_clr(dp, ZYNQMP_DP_PHY_RESET, ZYNQMP_DP_PHY_RESET_ALL_RESET); /* @@ -441,8 +437,6 @@ static void zynqmp_dp_phy_exit(struct zynqmp_dp *dp) ret); } - zynqmp_dp_reset(dp, true); - for (i = 0; i < dp->num_lanes; i++) { ret = phy_exit(dp->phy[i]); if (ret) @@ -1683,9 +1677,13 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) return PTR_ERR(dp->reset); } + ret = zynqmp_dp_reset(dp, false); + if (ret < 0) + return ret; + ret = zynqmp_dp_phy_probe(dp); if (ret) - return ret; + goto err_reset; /* Initialize the hardware. */ zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN, @@ -1697,7 +1695,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) ret = zynqmp_dp_phy_init(dp); if (ret) - return ret; + goto err_reset; zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 1); @@ -1709,15 +1707,18 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) zynqmp_dp_irq_handler, IRQF_ONESHOT, dev_name(dp->dev), dp); if (ret < 0) - goto error; + goto err_phy_exit; dev_dbg(dp->dev, "ZynqMP DisplayPort Tx probed with %u lanes\n", dp->num_lanes); return 0; -error: +err_phy_exit: zynqmp_dp_phy_exit(dp); +err_reset: + zynqmp_dp_reset(dp, true); + return ret; } @@ -1735,4 +1736,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub) zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, 0xffffffff); zynqmp_dp_phy_exit(dp); + zynqmp_dp_reset(dp, true); } |