drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
The call to mipi_dsi_host_register triggers a callback to mtk_dsi_bind,
which uses dev_get_drvdata to retrieve the mtk_dsi struct, so this
structure needs to be stored inside the driver data before invoking it.
As drvdata is currently uninitialized it leads to a crash when
registering the DSI DRM encoder right after acquiring
the mode_config.idr_mutex, blocking all subsequent DRM operations.
Fixes the following crash during mediatek-drm probe (tested on Xiaomi
Smart Clock x04g):
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000040
[...]
Modules linked in: mediatek_drm(+) drm_display_helper cec drm_client_lib
drm_dma_helper drm_kms_helper panel_simple
[...]
Call trace:
drm_mode_object_add+0x58/0x98 (P)
__drm_encoder_init+0x48/0x140
drm_encoder_init+0x6c/0xa0
drm_simple_encoder_init+0x20/0x34 [drm_kms_helper]
mtk_dsi_bind+0x34/0x13c [mediatek_drm]
component_bind_all+0x120/0x280
mtk_drm_bind+0x284/0x67c [mediatek_drm]
try_to_bring_up_aggregate_device+0x23c/0x320
__component_add+0xa4/0x198
component_add+0x14/0x20
mtk_dsi_host_attach+0x78/0x100 [mediatek_drm]
mipi_dsi_attach+0x2c/0x50
panel_simple_dsi_probe+0x4c/0x9c [panel_simple]
mipi_dsi_drv_probe+0x1c/0x28
really_probe+0xc0/0x3dc
__driver_probe_device+0x80/0x160
driver_probe_device+0x40/0x120
__device_attach_driver+0xbc/0x17c
bus_for_each_drv+0x88/0xf0
__device_attach+0x9c/0x1cc
device_initial_probe+0x54/0x60
bus_probe_device+0x34/0xa0
device_add+0x5b0/0x800
mipi_dsi_device_register_full+0xdc/0x16c
mipi_dsi_host_register+0xc4/0x17c
mtk_dsi_probe+0x10c/0x260 [mediatek_drm]
platform_probe+0x5c/0xa4
really_probe+0xc0/0x3dc
__driver_probe_device+0x80/0x160
driver_probe_device+0x40/0x120
__driver_attach+0xc8/0x1f8
bus_for_each_dev+0x7c/0xe0
driver_attach+0x24/0x30
bus_add_driver+0x11c/0x240
driver_register+0x68/0x130
__platform_register_drivers+0x64/0x160
mtk_drm_init+0x24/0x1000 [mediatek_drm]
do_one_initcall+0x60/0x1d0
do_init_module+0x54/0x240
load_module+0x1838/0x1dc0
init_module_from_file+0xd8/0xf0
__arm64_sys_finit_module+0x1b4/0x428
invoke_syscall.constprop.0+0x48/0xc8
do_el0_svc+0x3c/0xb8
el0_svc+0x34/0xe8
el0t_64_sync_handler+0xa0/0xe4
el0t_64_sync+0x198/0x19c
Code: 52800022 941004ab 2a0003f3 37f80040 (29005a80)
---[ end trace 0000000000000000 ]---
Signed-off-by: Luca Leonardo Scorcia <l.scorcia@gmail.com>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 4c2983852596..2358407b8a6b 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -1232,6 +1232,8 @@ static int mtk_dsi_probe(struct platform_device *pdev)
dsi->host.ops = &mtk_dsi_ops;
dsi->host.dev = dev;
+ platform_set_drvdata(pdev, dsi);
+
ret = mipi_dsi_host_register(&dsi->host);
if (ret < 0)
return dev_err_probe(dev, ret, "Failed to register DSI host\n");
@@ -1254,8 +1256,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
init_waitqueue_head(&dsi->irq_wait_queue);
- platform_set_drvdata(pdev, dsi);
-
dsi->bridge.of_node = dev->of_node;
dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
--
2.43.0Il 09/02/26 10:05, Luca Leonardo Scorcia ha scritto: > The call to mipi_dsi_host_register triggers a callback to mtk_dsi_bind, > which uses dev_get_drvdata to retrieve the mtk_dsi struct, so this > structure needs to be stored inside the driver data before invoking it. > > As drvdata is currently uninitialized it leads to a crash when > registering the DSI DRM encoder right after acquiring > the mode_config.idr_mutex, blocking all subsequent DRM operations. > > Fixes the following crash during mediatek-drm probe (tested on Xiaomi > Smart Clock x04g): > > Unable to handle kernel NULL pointer dereference at virtual address > 0000000000000040 > [...] > Modules linked in: mediatek_drm(+) drm_display_helper cec drm_client_lib > drm_dma_helper drm_kms_helper panel_simple > [...] > Call trace: > drm_mode_object_add+0x58/0x98 (P) > __drm_encoder_init+0x48/0x140 > drm_encoder_init+0x6c/0xa0 > drm_simple_encoder_init+0x20/0x34 [drm_kms_helper] > mtk_dsi_bind+0x34/0x13c [mediatek_drm] > component_bind_all+0x120/0x280 > mtk_drm_bind+0x284/0x67c [mediatek_drm] > try_to_bring_up_aggregate_device+0x23c/0x320 > __component_add+0xa4/0x198 > component_add+0x14/0x20 > mtk_dsi_host_attach+0x78/0x100 [mediatek_drm] > mipi_dsi_attach+0x2c/0x50 > panel_simple_dsi_probe+0x4c/0x9c [panel_simple] > mipi_dsi_drv_probe+0x1c/0x28 > really_probe+0xc0/0x3dc > __driver_probe_device+0x80/0x160 > driver_probe_device+0x40/0x120 > __device_attach_driver+0xbc/0x17c > bus_for_each_drv+0x88/0xf0 > __device_attach+0x9c/0x1cc > device_initial_probe+0x54/0x60 > bus_probe_device+0x34/0xa0 > device_add+0x5b0/0x800 > mipi_dsi_device_register_full+0xdc/0x16c > mipi_dsi_host_register+0xc4/0x17c > mtk_dsi_probe+0x10c/0x260 [mediatek_drm] > platform_probe+0x5c/0xa4 > really_probe+0xc0/0x3dc > __driver_probe_device+0x80/0x160 > driver_probe_device+0x40/0x120 > __driver_attach+0xc8/0x1f8 > bus_for_each_dev+0x7c/0xe0 > driver_attach+0x24/0x30 > bus_add_driver+0x11c/0x240 > driver_register+0x68/0x130 > __platform_register_drivers+0x64/0x160 > mtk_drm_init+0x24/0x1000 [mediatek_drm] > do_one_initcall+0x60/0x1d0 > do_init_module+0x54/0x240 > load_module+0x1838/0x1dc0 > init_module_from_file+0xd8/0xf0 > __arm64_sys_finit_module+0x1b4/0x428 > invoke_syscall.constprop.0+0x48/0xc8 > do_el0_svc+0x3c/0xb8 > el0_svc+0x34/0xe8 > el0t_64_sync_handler+0xa0/0xe4 > el0t_64_sync+0x198/0x19c > Code: 52800022 941004ab 2a0003f3 37f80040 (29005a80) > ---[ end trace 0000000000000000 ]--- > > Signed-off-by: Luca Leonardo Scorcia <l.scorcia@gmail.com> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> ... but wait, what have I just read? Xiaomi Smart Clock?! MT8167? Are you running upstream on this device? If so, why don't you also contribute a nice devicetree to get this device finally upstream?!?! :-) Cheers, Angelo > --- > drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c > index 4c2983852596..2358407b8a6b 100644 > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c > @@ -1232,6 +1232,8 @@ static int mtk_dsi_probe(struct platform_device *pdev) > > dsi->host.ops = &mtk_dsi_ops; > dsi->host.dev = dev; > + platform_set_drvdata(pdev, dsi); > + > ret = mipi_dsi_host_register(&dsi->host); > if (ret < 0) > return dev_err_probe(dev, ret, "Failed to register DSI host\n"); > @@ -1254,8 +1256,6 @@ static int mtk_dsi_probe(struct platform_device *pdev) > > init_waitqueue_head(&dsi->irq_wait_queue); > > - platform_set_drvdata(pdev, dsi); > - > dsi->bridge.of_node = dev->of_node; > dsi->bridge.type = DRM_MODE_CONNECTOR_DSI; >
Il giorno lun 9 feb 2026 alle ore 12:40 AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> ha scritto: > > Il 09/02/26 10:05, Luca Leonardo Scorcia ha scritto: > > The call to mipi_dsi_host_register triggers a callback to mtk_dsi_bind, > > which uses dev_get_drvdata to retrieve the mtk_dsi struct, so this > > structure needs to be stored inside the driver data before invoking it. > > > > As drvdata is currently uninitialized it leads to a crash when > > registering the DSI DRM encoder right after acquiring > > the mode_config.idr_mutex, blocking all subsequent DRM operations. > > > > Fixes the following crash during mediatek-drm probe (tested on Xiaomi > > Smart Clock x04g): > > > > Unable to handle kernel NULL pointer dereference at virtual address > > 0000000000000040 > > [...] > > ---[ end trace 0000000000000000 ]--- > > > > Signed-off-by: Luca Leonardo Scorcia <l.scorcia@gmail.com> > > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> > > ... but wait, what have I just read? Xiaomi Smart Clock?! MT8167? > > Are you running upstream on this device? > If so, why don't you also contribute a nice devicetree to get this device finally > upstream?!?! :-) That's correct! Most of the work had already been done by the wonderful people at postmarketOS, I just had to connect the dots. Some crucial patches (mt6392 regulator, mt8167 display nodes) were submitted in the past but weren't merged for various reasons. Just rebased on v6.19: https://pasteboard.co/6bXQeWlwUqmz.jpg I am trying to get it working as much as I can, then cleanup and submit. At the moment storage, usb networking, rtc, buttons, screen, touch, backlight, light/presence sensors, drm and gce are all working; still missing wifi/bt, audio and cpuidle. > Cheers, > Angelo > > > --- > > drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c > > index 4c2983852596..2358407b8a6b 100644 > > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c > > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c > > @@ -1232,6 +1232,8 @@ static int mtk_dsi_probe(struct platform_device *pdev) > > > > dsi->host.ops = &mtk_dsi_ops; > > dsi->host.dev = dev; > > + platform_set_drvdata(pdev, dsi); > > + > > ret = mipi_dsi_host_register(&dsi->host); > > if (ret < 0) > > return dev_err_probe(dev, ret, "Failed to register DSI host\n"); > > @@ -1254,8 +1256,6 @@ static int mtk_dsi_probe(struct platform_device *pdev) > > > > init_waitqueue_head(&dsi->irq_wait_queue); > > > > - platform_set_drvdata(pdev, dsi); > > - > > dsi->bridge.of_node = dev->of_node; > > dsi->bridge.type = DRM_MODE_CONNECTOR_DSI; > > > > -- Luca Leonardo Scorcia l.scorcia@gmail.com
© 2016 - 2026 Red Hat, Inc.