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
Il 09/02/26 19:46, Luca Leonardo Scorcia ha scritto: > 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 Oh that's so cool! > > 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. > You got an astonishingly big amount of features working fine then. That is practically almost everything. I do encourage you to send all this good stuff upstream, as I'd anyway not really expect your v1 to be perfect (however, I'm ready to get pleasantly surprised, so please do?!). Getting your current state correctly upstreamed makes you able to avoid refactors during development and to actually get all the rest here upstream in relatively less time. After all, while it would be nice to have something complete and 100% working in the first-ever iteration, you got really a lot of nice stuff there - and from an upstream point of view, a device with this percentage of completion would be perfectly acceptable. Sending patches to add up more features later, even one by one, is just a regular workflow, so that'd be perfectly acceptable as well. What is not acceptable is non-functional placeholders that get deleted entirely with subsequent patches (like adding a UART node with fake pinctrl because the bootloader leaves that configured, but then deleting everything and refactoring to make it proper ... bar exceptional cases, of course, everything is always relative to specific situations). Ultimately, it's your choice though, of course. Keep up the good work! Cheers, Angelo >> 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; >>> >> >> > >
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