Re: [PATCH] drm/msm: Initialize MDSS irq domain at probe time

From: Dmitry Baryshkov
Date: Thu Nov 25 2021 - 17:44:24 EST

On 25/11/2021 18:09, AngeloGioacchino Del Regno wrote:
Since commit 8f59ee9a570c ("drm/msm/dsi: Adjust probe order"), the
DSI host gets initialized earlier, but this caused unability to probe
the entire stack of components because they all depend on interrupts
coming from the main `mdss` node (mdp5, or dpu1).

To fix this issue, also anticipate probing mdp5 or dpu1 by initializing
them at msm_pdev_probe() time: this will make sure that we add the
required interrupt controller mapping before dsi and/or other components
try to initialize, finally satisfying the dependency.

While at it, also change the allocation of msm_drm_private to use the
devm variant of kzalloc().

Fixes: 8f59ee9a570c ("drm/msm/dsi: Adjust probe order")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>

If device is not fully bound (e.g. DSI host could not bind the panel), this patch causes the following oops on reboot:

[ 75.011942] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
[ 75.020974] Mem abort info:
[ 75.023859] ESR = 0x96000006
[ 75.027013] EC = 0x25: DABT (current EL), IL = 32 bits
[ 75.032480] SET = 0, FnV = 0
[ 75.035627] EA = 0, S1PTW = 0
[ 75.038861] FSC = 0x06: level 2 translation fault
[ 75.043876] Data abort info:
[ 75.046847] ISV = 0, ISS = 0x00000006
[ 75.050796] CM = 0, WnR = 0
[ 75.053857] user pgtable: 4k pages, 48-bit VAs, pgdp=00000001102b3000
[ 75.060478] [0000000000000030] pgd=080000011035d003, p4d=080000011035d003, pud=080000011035f003, pmd=0000000000000000
[ 75.071380] Internal error: Oops: 96000006 [#1] SMP
[ 75.076388] Modules linked in:
[ 75.079530] CPU: 0 PID: 1442 Comm: reboot Not tainted 5.16.0-rc1-00046-g2207fd610cf4-dirty #185
[ 75.088460] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
[ 75.095345] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 75.102496] pc : drm_atomic_state_alloc+0x14/0x74
[ 75.107335] lr : drm_atomic_helper_disable_all+0x20/0x210
[ 75.112885] sp : ffff80001480bb70
[ 75.116298] x29: ffff80001480bb70 x28: ffff0c8753505400 x27: 0000000000000000
[ 75.123626] x26: ffff0c874097d890 x25: ffffaa357b610e00 x24: 0000000000000000
[ 75.130954] x23: ffffaa357bdaa030 x22: ffffaa357bdfd2d8 x21: ffff80001480bbf8
[ 75.138282] x20: ffff0c87469bd800 x19: ffff0c87469bd800 x18: ffffffffffffffff
[ 75.145608] x17: 000000000000000e x16: 0000000000000001 x15: ffff80009480ba3d
[ 75.152934] x14: 0000000000000004 x13: 0000000000000000 x12: ffff0c87452c1288
[ 75.160261] x11: 0000000000000003 x10: ffff0c87452c1240 x9 : 0000000000000001
[ 75.167588] x8 : ffff80001480bc38 x7 : 0000000000000000 x6 : ffff0c874f63d300
[ 75.174914] x5 : 0000000000000000 x4 : ffffaa357b582d30 x3 : 0000000000000000
[ 75.182240] x2 : ffff80001480bc20 x1 : 0000000000000000 x0 : ffff0c87469bd800
[ 75.189568] Call trace:
[ 75.192092] drm_atomic_state_alloc+0x14/0x74
[ 75.196571] drm_atomic_helper_disable_all+0x20/0x210
[ 75.201765] drm_atomic_helper_shutdown+0x80/0x130
[ 75.206683] msm_pdev_shutdown+0x2c/0x40
[ 75.210717] platform_shutdown+0x28/0x40
[ 75.214751] device_shutdown+0x15c/0x450
[ 75.218785] __do_sys_reboot+0x218/0x2a0
[ 75.222819] __arm64_sys_reboot+0x28/0x34
[ 75.226937] invoke_syscall+0x48/0x114
[ 75.230794] el0_svc_common.constprop.0+0xd4/0xfc
[ 75.235626] do_el0_svc+0x28/0x90
[ 75.239030] el0_svc+0x28/0x80
[ 75.242174] el0t_64_sync_handler+0xa4/0x130
[ 75.246567] el0t_64_sync+0x1a0/0x1a4
[ 75.250338] Code: a9be7bfd 910003fd a90153f3 f9418c01 (f9401821)
[ 75.256599] ---[ end trace d90b41486de58d22 ]---


The following patch fixes it:

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 41c6a9f9dd34..5a92417d21d0 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1435,7 +1435,7 @@ static void msm_pdev_shutdown(struct
struct drm_device *drm = platform_get_drvdata(pdev);
struct msm_drm_private *priv = drm ? drm->dev_private : NULL;

- if (!priv || !priv->kms)
+ if (!priv || !priv->kms || !drm->mode_config.funcs)
return;

drm_atomic_helper_shutdown(drm);


---
drivers/gpu/drm/msm/msm_drv.c | 81 ++++++++++++++++-------------------
1 file changed, 38 insertions(+), 43 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 7936e8d498dd..790acf4993c0 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -512,45 +512,12 @@ static int msm_init_vram(struct drm_device *dev)
static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
{
struct platform_device *pdev = to_platform_device(dev);
- struct drm_device *ddev;
- struct msm_drm_private *priv;
- struct msm_kms *kms;
- struct msm_mdss *mdss;
+ struct drm_device *ddev = platform_get_drvdata(pdev);
+ struct msm_drm_private *priv = ddev->dev_private;
+ struct msm_kms *kms = priv->kms;
+ struct msm_mdss *mdss = priv->mdss;
int ret, i;
- ddev = drm_dev_alloc(drv, dev);
- if (IS_ERR(ddev)) {
- DRM_DEV_ERROR(dev, "failed to allocate drm_device\n");
- return PTR_ERR(ddev);
- }
-
- platform_set_drvdata(pdev, ddev);
-
- priv = kzalloc(sizeof(*priv), GFP_KERNEL);
- if (!priv) {
- ret = -ENOMEM;
- goto err_put_drm_dev;
- }
-
- ddev->dev_private = priv;
- priv->dev = ddev;
-
- switch (get_mdp_ver(pdev)) {
- case KMS_MDP5:
- ret = mdp5_mdss_init(ddev);
- break;
- case KMS_DPU:
- ret = dpu_mdss_init(ddev);
- break;
- default:
- ret = 0;
- break;
- }
- if (ret)
- goto err_free_priv;
-
- mdss = priv->mdss;
-
priv->wq = alloc_ordered_workqueue("msm", 0);
priv->hangcheck_period = DRM_MSM_HANGCHECK_DEFAULT_PERIOD;
@@ -685,11 +652,6 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
err_destroy_mdss:
if (mdss && mdss->funcs)
mdss->funcs->destroy(ddev);
-err_free_priv:
- kfree(priv);
-err_put_drm_dev:
- drm_dev_put(ddev);
- platform_set_drvdata(pdev, NULL);
return ret;
}
@@ -1382,12 +1344,42 @@ static const struct component_master_ops msm_drm_ops = {
static int msm_pdev_probe(struct platform_device *pdev)
{
struct component_match *match = NULL;
+ struct msm_drm_private *priv;
+ struct drm_device *ddev;
int ret;
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ ddev = drm_dev_alloc(&msm_driver, &pdev->dev);
+ if (IS_ERR(ddev)) {
+ DRM_DEV_ERROR(&pdev->dev, "failed to allocate drm_device\n");
+ return PTR_ERR(ddev);
+ }
+
+ platform_set_drvdata(pdev, ddev);
+ ddev->dev_private = priv;
+ priv->dev = ddev;
+
+ switch (get_mdp_ver(pdev)) {
+ case KMS_MDP5:
+ ret = mdp5_mdss_init(ddev);
+ break;
+ case KMS_DPU:
+ ret = dpu_mdss_init(ddev);
+ break;
+ default:
+ ret = 0;
+ break;
+ }
+ if (ret)
+ goto err_put_drm_dev;
+
if (get_mdp_ver(pdev)) {
ret = add_display_components(pdev, &match);
if (ret)
- return ret;
+ goto fail;
}
ret = add_gpu_components(&pdev->dev, &match);
@@ -1409,6 +1401,9 @@ static int msm_pdev_probe(struct platform_device *pdev)
fail:
of_platform_depopulate(&pdev->dev);
+err_put_drm_dev:
+ drm_dev_put(ddev);
+ platform_set_drvdata(pdev, NULL);
return ret;
}



--
With best wishes
Dmitry