[PATCH 0/2] Fixes kernel Oops in imx-drm drivers

[PATCH 0/2] Fixes kernel Oops in imx-drm drivers

[Shawn Guo]

In my testing of bind/unbind (and insmod/rmmod) on imx-drm drivers,
a couple of kernel Oops are seen.  These two patches are trying to
fix them.

Shawn Guo (2):
  imx-drm: imx-ldb: fix kernel Oops in imx_ldb_unbind()
  imx-drm: ipuv3-plane: fix kernel Oops in ipu_dp_put()

 drivers/staging/imx-drm/imx-ldb.c     | 2 ++
 drivers/staging/imx-drm/ipuv3-plane.c | 9 ++-------
 2 files changed, 4 insertions(+), 7 deletions(-)

-- 
1.9.1

[PATCH 1/2] imx-drm: imx-ldb: fix kernel Oops in imx_ldb_unbind()

[Shawn Guo]

Unbinding imx-ldb driver on imx6q-sabresd board triggers a kernel Oops
as below.

$ echo 2000000.aips-bus\:ldb\@020e0008 > unbind
[  423.031003] Console: switching to colour dummy device 80x30
[  423.052505] drm_kms_helper: drm: unregistered panic notifier
[  423.137082] Unable to handle kernel NULL pointer dereference at virtual address 0000001c
[  423.145185] pgd = bd6cc000
[  423.147937] [0000001c] *pgd=4cd23831, *pte=00000000, *ppte=00000000
[  423.154271] Internal error: Oops: 17 [#1] SMP ARM
[  423.158983] Modules linked in:
[  423.162067] CPU: 1 PID: 1854 Comm: bash Not tainted 3.17.0-rc1-00029-gd7473b0c2e59-dirty #397
[  423.170599] task: be21f500 ti: bd446000 task.ti: bd446000
[  423.176021] PC is at imx_ldb_unbind+0x28/0x50
[  423.180393] LR is at component_unbind+0x38/0x70
[  423.184932] pc : [<804dddd0>]    lr : [<80362e5c>]    psr: 20000013
[  423.184932] sp : bd447d78  ip : bd447d98  fp : bd447d94
[  423.196416] r10: bd7cbc00  r9 : bd7cbc0c  r8 : 0000001e
[  423.201648] r7 : bd84d010  r6 : 000003a8  r5 : 00000001  r4 : bd84d010
[  423.208181] r3 : 00000000  r2 : bd942000  r1 : be1a8410  r0 : bd84d020
[  423.214717] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[  423.221858] Control: 10c5387d  Table: 4d6cc04a  DAC: 00000015
[  423.227611] Process bash (pid: 1854, stack limit = 0xbd446240)
[  423.233450] Stack: (0xbd447d78 to 0xbd448000)
[  423.237815] 7d60:                                                       bd931dc0 bd931b80
[  423.246003] 7d80: bd942000 806ec058 bd447db4 bd447d98 80362e5c 804dddb4 bd8df400 be1a2c10
[  423.254190] 7da0: bd931b80 bd931dc0 bd447dd4 bd447db8 80362f0c 80362e30 be21f500 bd942000
[  423.262376] 7dc0: bd8ed910 be1a2c10 bd447dec bd447dd8 804dc740 80362ea0 bd942000 bd942000
[  423.270563] 7de0: bd447e0c bd447df0 80345cdc 804dc718 00000000 bd942000 80965ec0 be1a2c10
[  423.278749] 7e00: bd447e24 bd447e10 803467a0 80345cbc 804dc6d4 bd931b80 bd447e34 bd447e28
[  423.286936] 7e20: 804dc6e8 8034677c bd447e4c bd447e38 80362c80 804dc6e0 80965ec0 bd931dc0
[  423.295123] 7e40: bd447e6c bd447e50 80362d28 80362c60 be1a2c10 80987418 809661f8 0000001e
[  423.303310] 7e60: bd447e7c bd447e70 804dde10 80362cac bd447e8c bd447e80 80368ac0 804dde04
[  423.311497] 7e80: bd447ea4 bd447e90 8036721c 80368aac be1a2c44 be1a2c10 bd447ebc bd447ea8
[  423.319683] 7ea0: 80367298 803671b0 be1a2c10 80987418 bd447edc bd447ec0 80366398 8036727c
[  423.327870] 7ec0: bd7cbc00 0000001e bd7760c0 bd447f78 bd447eec bd447ee0 80365acc 80366340
[  423.336056] 7ee0: bd447f0c bd447ef0 8014b224 80365ab0 8014b1d0 00000000 00000000 bd7760c0
[  423.344254] 7f00: bd447f44 bd447f10 8014a564 8014b1dc 00000000 00000000 00000001 bd4d5900
[  423.352457] 7f20: 0000001e 01a35c08 bd447f78 0000001e bd446000 01a35c08 bd447f74 bd447f48
[  423.360660] 7f40: 800e7c50 8014a4a8 80102c04 80102b84 00000000 00000000 bd4d5900 bd4d5900
[  423.368863] 7f60: 0000001e 01a35c08 bd447fa4 bd447f78 800e8074 800e7bb4 00000000 00000000
[  423.377066] 7f80: 76f825e0 0000001e 01a35c08 00000004 8000ed64 00000000 00000000 bd447fa8
[  423.385269] 7fa0: 8000eba0 800e803c 76f825e0 0000001e 00000001 01a35c08 0000001e 00000000
[  423.393472] 7fc0: 76f825e0 0000001e 01a35c08 00000004 7eeb6a9c 000ad08c 00000000 01a4b888
[  423.401674] 7fe0: 0000001e 7eeb6a20 76ef196d 76f2a6bc 40000010 00000001 00000000 00000000
[  423.409864] Backtrace:
[  423.412372] [<804ddda8>] (imx_ldb_unbind) from [<80362e5c>] (component_unbind+0x38/0x70)
[  423.420479]  r7:806ec058 r6:bd942000 r5:bd931b80 r4:bd931dc0
[  423.426265] [<80362e24>] (component_unbind) from [<80362f0c>] (component_unbind_all+0x78/0xb0)
[  423.434893]  r5:bd931dc0 r4:bd931b80
[  423.438548] [<80362e94>] (component_unbind_all) from [<804dc740>] (imx_drm_driver_unload+0x34/0x58)
[  423.447610]  r6:be1a2c10 r5:bd8ed910 r4:bd942000 r3:be21f500
[  423.453401] [<804dc70c>] (imx_drm_driver_unload) from [<80345cdc>] (drm_dev_unregister+0x2c/0xa0)
[  423.462289]  r5:bd942000 r4:bd942000
[  423.465942] [<80345cb0>] (drm_dev_unregister) from [<803467a0>] (drm_put_dev+0x30/0x6c)
[  423.473963]  r6:be1a2c10 r5:80965ec0 r4:bd942000 r3:00000000
[  423.479748] [<80346770>] (drm_put_dev) from [<804dc6e8>] (imx_drm_unbind+0x14/0x18)
[  423.487420]  r4:bd931b80 r3:804dc6d4
[  423.491072] [<804dc6d4>] (imx_drm_unbind) from [<80362c80>] (take_down_master+0x2c/0x4c)
[  423.499195] [<80362c54>] (take_down_master) from [<80362d28>] (component_del+0x88/0xd0)
[  423.507214]  r4:bd931dc0 r3:80965ec0
[  423.510868] [<80362ca0>] (component_del) from [<804dde10>] (imx_ldb_remove+0x18/0x24)
[  423.518714]  r7:0000001e r6:809661f8 r5:80987418 r4:be1a2c10
[  423.524501] [<804dddf8>] (imx_ldb_remove) from [<80368ac0>] (platform_drv_remove+0x20/0x24)
[  423.532884] [<80368aa0>] (platform_drv_remove) from [<8036721c>] (__device_release_driver+0x78/0xcc)
[  423.542045] [<803671a4>] (__device_release_driver) from [<80367298>] (device_release_driver+0x28/0x34)
[  423.551367]  r5:be1a2c10 r4:be1a2c44
[  423.555015] [<80367270>] (device_release_driver) from [<80366398>] (unbind_store+0x64/0x9c)
[  423.563381]  r5:80987418 r4:be1a2c10
[  423.567034] [<80366334>] (unbind_store) from [<80365acc>] (drv_attr_store+0x28/0x34)
[  423.574794]  r7:bd447f78 r6:bd7760c0 r5:0000001e r4:bd7cbc00
[  423.580580] [<80365aa4>] (drv_attr_store) from [<8014b224>] (sysfs_kf_write+0x54/0x58)
[  423.588526] [<8014b1d0>] (sysfs_kf_write) from [<8014a564>] (kernfs_fop_write+0xc8/0x188)
[  423.596720]  r6:bd7760c0 r5:00000000 r4:00000000 r3:8014b1d0
[  423.602508] [<8014a49c>] (kernfs_fop_write) from [<800e7c50>] (vfs_write+0xa8/0x1b0)
[  423.610268]  r10:01a35c08 r9:bd446000 r8:0000001e r7:bd447f78 r6:01a35c08 r5:0000001e
[  423.618234]  r4:bd4d5900
[  423.620819] [<800e7ba8>] (vfs_write) from [<800e8074>] (SyS_write+0x44/0x90)
[  423.627884]  r10:01a35c08 r8:0000001e r7:bd4d5900 r6:bd4d5900 r5:00000000 r4:00000000
[  423.635873] [<800e8030>] (SyS_write) from [<8000eba0>] (ret_fast_syscall+0x0/0x48)
[  423.643459]  r10:00000000 r8:8000ed64 r7:00000004 r6:01a35c08 r5:0000001e r4:76f825e0
[  423.651433] Code: e0247596 e2855001 e2840010 e59430a0 (e593301c)
[  423.657672] ---[ end trace 8e42829dfb82309e ]---

It's caused by that function imx_ldb_unbind() always tries to destroy
both LDB channels without checking if both channels are created in
imx_ldb_bind().  It's pretty often that only one of the LDB channels is
created just like the case of imx6q-sabresd board, and the
connector/encoder's destroy() function pointer of the other channel
will be invalid.

Fix the issue by checking if the LDB channel is actually created/valid
before calling into its connector/encoder's destroy() function.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
---
 drivers/staging/imx-drm/imx-ldb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/imx-drm/imx-ldb.c b/drivers/staging/imx-drm/imx-ldb.c
index 7e3f019d7e72..795794fff034 100644
--- a/drivers/staging/imx-drm/imx-ldb.c
+++ b/drivers/staging/imx-drm/imx-ldb.c
@@ -574,6 +574,8 @@ static void imx_ldb_unbind(struct device *dev, struct device *master,
 	for (i = 0; i < 2; i++) {
 		struct imx_ldb_channel *channel = &imx_ldb->channel[i];
 
+		if (channel->ldb == NULL)
+			continue;
 		channel->connector.funcs->destroy(&channel->connector);
 		channel->encoder.funcs->destroy(&channel->encoder);
 	}
-- 
1.9.1

[PATCH 1/2] imx-drm: imx-ldb: fix kernel Oops in imx_ldb_unbind()

[Philipp Zabel]

Am Dienstag, den 19.08.2014, 17:49 +0800 schrieb Shawn Guo:
> Unbinding imx-ldb driver on imx6q-sabresd board triggers a kernel Oops
> as below.
> 
> $ echo 2000000.aips-bus\:ldb\@020e0008 > unbind
[...]
> Fix the issue by checking if the LDB channel is actually created/valid
> before calling into its connector/encoder's destroy() function.
> 
> Signed-off-by: Shawn Guo <shawn.guo@freescale.com>

Acked-by: Philipp Zabel <p.zabel@pengutronix.de>

Tested on Nitrogen6X with LVDS panel.

regards
Philipp

[PATCH 2/2] imx-drm: ipuv3-plane: fix kernel Oops in ipu_dp_put()

[Shawn Guo]

Unbinding imx-hdmi or imx-ldb driver triggers a kernel Oops in function
ipu_dp_put() as below.

$ echo 120000.hdmi > /sys/devices/soc0/soc/2000000.aips-bus/120000.hdmi/driver/unbind
[   66.411700] Console: switching to colour dummy device 80x30
[   66.432543] drm_kms_helper: drm: unregistered panic notifier
[   66.515313] Unable to handle kernel NULL pointer dereference at virtual address 00000004
[   66.523445] pgd = bc494000
[   66.526161] [00000004] *pgd=4da3b831, *pte=00000000, *ppte=00000000
[   66.532521] Internal error: Oops: 817 [#1] SMP ARM
[   66.537320] Modules linked in:
[   66.540403] CPU: 1 PID: 1874 Comm: bash Not tainted 3.17.0-rc1-00030-gcbc339c9c4c0-dirty #398
[   66.548937] task: bc697500 ti: bc468000 task.ti: bc468000
[   66.554354] PC is at ipu_dp_put+0x10/0x18
[   66.558376] LR is at ipu_plane_dpms+0x60/0x8c
[   66.562743] pc : [<80360904>]    lr : [<804df730>]    psr: 20000013
[   66.562743] sp : bc469d50  ip : bc469d60  fp : bc469d5c
[   66.574227] r10: 00100100  r9 : bd94a474  r8 : 00200200
[   66.579459] r7 : bd94a3f4  r6 : bd94a400  r5 : 00000003  r4 : bd943c00
[   66.585992] r3 : 00000000  r2 : 00000000  r1 : bc6979d0  r0 : 00000000
[   66.592528] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   66.599670] Control: 10c5387d  Table: 4c49404a  DAC: 00000015
[   66.605422] Process bash (pid: 1874, stack limit = 0xbc468240)
[   66.611262] Stack: (0xbc469d50 to 0xbc46a000)
[   66.615629] 9d40:                                     bc469d74 bc469d60 804df730 80360900
[   66.623817] 9d60: bd943c00 bd94a000 bc469d8c bc469d78 804df788 804df6dc 00000000 bd943c00
[   66.632005] 9d80: bc469da4 bc469d90 804df7e8 804df768 804df7c0 bd943e00 bc469dd4 bc469da8
[   66.640202] 9da0: 8034e5b8 804df7cc bc697500 bd94a000 bd932a90 be1a3010 806ec3c0 0000000c
[   66.648406] 9dc0: bd5a4a0c bd5a4a00 bc469dec bc469dd8 804dc750 8034e3f4 bd94a000 bd94a000
[   66.656609] 9de0: bc469e0c bc469df0 80345cdc 804dc718 00000000 bd94a000 80965ec0 be1a3010
[   66.664813] 9e00: bc469e24 bc469e10 803467a0 80345cbc 804dc6d4 bd930a40 bc469e34 bc469e28
[   66.673017] 9e20: 804dc6e8 8034677c bc469e4c bc469e38 80362c80 804dc6e0 bd930fc0 bd932100
[   66.681219] 9e40: bc469e6c bc469e50 80362d28 80362c60 be1a3010 80987574 809661f8 0000000c
[   66.689423] 9e60: bc469e7c bc469e70 804e00f8 80362cac bc469e8c bc469e80 80368ac0 804e00ec
[   66.697627] 9e80: bc469ea4 bc469e90 8036721c 80368aac be1a3044 be1a3010 bc469ebc bc469ea8
[   66.705831] 9ea0: 80367298 803671b0 be1a3010 80987574 bc469edc bc469ec0 80366398 8036727c
[   66.714033] 9ec0: bd5a4a00 0000000c bd4fc580 bc469f78 bc469eec bc469ee0 80365acc 80366340
[   66.722237] 9ee0: bc469f0c bc469ef0 8014b224 80365ab0 8014b1d0 00000000 00000000 bd4fc580
[   66.730439] 9f00: bc469f44 bc469f10 8014a564 8014b1dc 00000000 00000000 00000001 bd66d040
[   66.738644] 9f20: 0000000c 0032ac08 bc469f78 0000000c bc468000 0032ac08 bc469f74 bc469f48
[   66.746847] 9f40: 800e7c50 8014a4a8 80102c04 80102b84 00000000 00000000 bd66d040 bd66d040
[   66.755050] 9f60: 0000000c 0032ac08 bc469fa4 bc469f78 800e8074 800e7bb4 00000000 00000000
[   66.763253] 9f80: 76ec85e0 0000000c 0032ac08 00000004 8000ed64 00000000 00000000 bc469fa8
[   66.771455] 9fa0: 8000eba0 800e803c 76ec85e0 0000000c 00000001 0032ac08 0000000c 00000000
[   66.779659] 9fc0: 76ec85e0 0000000c 0032ac08 00000004 7ee29a9c 000ad08c 00000000 003402e8
[   66.787862] 9fe0: 0000000c 7ee29a20 76e3796d 76e706bc 40000010 00000001 00000000 00000000
[   66.796052] Backtrace:
[   66.798558] [<803608f4>] (ipu_dp_put) from [<804df730>] (ipu_plane_dpms+0x60/0x8c)
[   66.806159] [<804df6d0>] (ipu_plane_dpms) from [<804df788>] (ipu_disable_plane+0x2c/0x64)
[   66.814352]  r5:bd94a000 r4:bd943c00
[   66.818002] [<804df75c>] (ipu_disable_plane) from [<804df7e8>] (ipu_plane_destroy+0x28/0x64)
[   66.826456]  r4:bd943c00 r3:00000000
[   66.830112] [<804df7c0>] (ipu_plane_destroy) from [<8034e5b8>] (drm_mode_config_cleanup+0x1d0/0x274)
[   66.839260]  r4:bd943e00 r3:804df7c0
[   66.842921] [<8034e3e8>] (drm_mode_config_cleanup) from [<804dc750>] (imx_drm_driver_unload+0x44/0x58)
[   66.852243]  r10:bd5a4a00 r9:bd5a4a0c r8:0000000c r7:806ec3c0 r6:be1a3010 r5:bd932a90
[   66.860210]  r4:bd94a000 r3:bc697500
[   66.863870] [<804dc70c>] (imx_drm_driver_unload) from [<80345cdc>] (drm_dev_unregister+0x2c/0xa0)
[   66.872758]  r5:bd94a000 r4:bd94a000
[   66.876411] [<80345cb0>] (drm_dev_unregister) from [<803467a0>] (drm_put_dev+0x30/0x6c)
[   66.884431]  r6:be1a3010 r5:80965ec0 r4:bd94a000 r3:00000000
[   66.890214] [<80346770>] (drm_put_dev) from [<804dc6e8>] (imx_drm_unbind+0x14/0x18)
[   66.897886]  r4:bd930a40 r3:804dc6d4
[   66.901542] [<804dc6d4>] (imx_drm_unbind) from [<80362c80>] (take_down_master+0x2c/0x4c)
[   66.909663] [<80362c54>] (take_down_master) from [<80362d28>] (component_del+0x88/0xd0)
[   66.917682]  r4:bd932100 r3:bd930fc0
[   66.921334] [<80362ca0>] (component_del) from [<804e00f8>] (imx_hdmi_platform_remove+0x18/0x24)
[   66.930048]  r7:0000000c r6:809661f8 r5:80987574 r4:be1a3010
[   66.935838] [<804e00e0>] (imx_hdmi_platform_remove) from [<80368ac0>] (platform_drv_remove+0x20/0x24)
[   66.945089] [<80368aa0>] (platform_drv_remove) from [<8036721c>] (__device_release_driver+0x78/0xcc)
[   66.954251] [<803671a4>] (__device_release_driver) from [<80367298>] (device_release_driver+0x28/0x34)
[   66.963572]  r5:be1a3010 r4:be1a3044
[   66.967221] [<80367270>] (device_release_driver) from [<80366398>] (unbind_store+0x64/0x9c)
[   66.975588]  r5:80987574 r4:be1a3010
[   66.979246] [<80366334>] (unbind_store) from [<80365acc>] (drv_attr_store+0x28/0x34)
[   66.987005]  r7:bc469f78 r6:bd4fc580 r5:0000000c r4:bd5a4a00
[   66.992793] [<80365aa4>] (drv_attr_store) from [<8014b224>] (sysfs_kf_write+0x54/0x58)
[   67.000741] [<8014b1d0>] (sysfs_kf_write) from [<8014a564>] (kernfs_fop_write+0xc8/0x188)
[   67.008933]  r6:bd4fc580 r5:00000000 r4:00000000 r3:8014b1d0
[   67.014722] [<8014a49c>] (kernfs_fop_write) from [<800e7c50>] (vfs_write+0xa8/0x1b0)
[   67.022482]  r10:0032ac08 r9:bc468000 r8:0000000c r7:bc469f78 r6:0032ac08 r5:0000000c
[   67.030450]  r4:bd66d040
[   67.033037] [<800e7ba8>] (vfs_write) from [<800e8074>] (SyS_write+0x44/0x90)
[   67.040102]  r10:0032ac08 r8:0000000c r7:bd66d040 r6:bd66d040 r5:00000000 r4:00000000
[   67.048092] [<800e8030>] (SyS_write) from [<8000eba0>] (ret_fast_syscall+0x0/0x48)
[   67.055677]  r10:00000000 r8:8000ed64 r7:00000004 r6:0032ac08 r5:0000000c r4:76ec85e0
[   67.063656] Code: e1a0c00d e92dd800 e24cb004 e3a03000 (e5c03004)
[   67.069914] ---[ end trace d739aae75ff0ad16 ]---

>From the call stack, the issue is caused by that ipu_dp_put() is called
from ipu_plane_dpms() with ipu_plane->dp being NULL.  Rather than
being called unconditionally, ipu_dp_put() should be called only when
ipu_plane->dp is valid, just like what ipu_plane_put_resources() does.
Acutally, all those ipu_*_put() calls in ipu_plane_dpms() are
unnecessary, because the only occurrence of ipu_plane_dpms() with 'mode'
not being DRM_MODE_DPMS_ON is from function ipu_disable_plane(), which
already has a ipu_plane_put_resources() call right after
ipu_plane_dpms().

The patch fixes above kernel Oops by removing those buggy and
unnecessary ipu_*_put() calls from ipu_plane_dpms().

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
---
 drivers/staging/imx-drm/ipuv3-plane.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
index 6f393a11f44d..a79ae7731a03 100644
--- a/drivers/staging/imx-drm/ipuv3-plane.c
+++ b/drivers/staging/imx-drm/ipuv3-plane.c
@@ -274,15 +274,10 @@ static void ipu_plane_dpms(struct ipu_plane *ipu_plane, int mode)
 	if (enable == ipu_plane->enabled)
 		return;
 
-	if (enable) {
+	if (enable)
 		ipu_plane_enable(ipu_plane);
-	} else {
+	else
 		ipu_plane_disable(ipu_plane);
-
-		ipu_idmac_put(ipu_plane->ipu_ch);
-		ipu_dmfc_put(ipu_plane->dmfc);
-		ipu_dp_put(ipu_plane->dp);
-	}
 }
 
 /*
-- 
1.9.1

[PATCH 2/2] imx-drm: ipuv3-plane: fix kernel Oops in ipu_dp_put()

[Philipp Zabel]

Hi Shawn,

Am Dienstag, den 19.08.2014, 17:49 +0800 schrieb Shawn Guo:
> Unbinding imx-hdmi or imx-ldb driver triggers a kernel Oops in function
> ipu_dp_put() as below.
> 
> $ echo 120000.hdmi > /sys/devices/soc0/soc/2000000.aips-bus/120000.hdmi/driver/unbind
[...]
> From the call stack, the issue is caused by that ipu_dp_put() is called
> from ipu_plane_dpms() with ipu_plane->dp being NULL.  Rather than
> being called unconditionally, ipu_dp_put() should be called only when
> ipu_plane->dp is valid, just like what ipu_plane_put_resources() does.
> Acutally, all those ipu_*_put() calls in ipu_plane_dpms() are
> unnecessary, because the only occurrence of ipu_plane_dpms() with 'mode'
> not being DRM_MODE_DPMS_ON is from function ipu_disable_plane(), which
> already has a ipu_plane_put_resources() call right after
> ipu_plane_dpms().
> 
> The patch fixes above kernel Oops by removing those buggy and
> unnecessary ipu_*_put() calls from ipu_plane_dpms().
> 
> Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
> ---
>  drivers/staging/imx-drm/ipuv3-plane.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
> index 6f393a11f44d..a79ae7731a03 100644
> --- a/drivers/staging/imx-drm/ipuv3-plane.c
> +++ b/drivers/staging/imx-drm/ipuv3-plane.c
> @@ -274,15 +274,10 @@ static void ipu_plane_dpms(struct ipu_plane *ipu_plane, int mode)
>  	if (enable == ipu_plane->enabled)
>  		return;
>  
> -	if (enable) {
> +	if (enable)
>  		ipu_plane_enable(ipu_plane);
> -	} else {
> +	else
>  		ipu_plane_disable(ipu_plane);
> -
> -		ipu_idmac_put(ipu_plane->ipu_ch);
> -		ipu_dmfc_put(ipu_plane->dmfc);
> -		ipu_dp_put(ipu_plane->dp);
> -	}
>  }
>  
>  /*

we could then remove ipu_plane_dpms completely:

---
 drivers/staging/imx-drm/ipuv3-plane.c | 23 ++++-------------------
 1 file changed, 4 insertions(+), 19 deletions(-)

diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
index b2d1bb2..6987e16 100644
--- a/drivers/staging/imx-drm/ipuv3-plane.c
+++ b/drivers/staging/imx-drm/ipuv3-plane.c
@@ -290,23 +290,6 @@ void ipu_plane_disable(struct ipu_plane *ipu_plane)
 		ipu_dp_disable(ipu_plane->ipu);
 }
 
-static void ipu_plane_dpms(struct ipu_plane *ipu_plane, int mode)
-{
-	bool enable;
-
-	DRM_DEBUG_KMS("mode = %d", mode);
-
-	enable = (mode == DRM_MODE_DPMS_ON);
-
-	if (enable == ipu_plane->enabled)
-		return;
-
-	if (enable)
-		ipu_plane_enable(ipu_plane);
-	else
-		ipu_plane_disable(ipu_plane);
-}
-
 /*
  * drm_plane API
  */
@@ -340,7 +323,8 @@ static int ipu_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 				plane->crtc, crtc);
 	plane->crtc = crtc;
 
-	ipu_plane_dpms(ipu_plane, DRM_MODE_DPMS_ON);
+	if (!ipu_plane->enabled)
+		ipu_plane_enable(ipu_plane);
 
 	return 0;
 }
@@ -351,7 +335,8 @@ static int ipu_disable_plane(struct drm_plane *plane)
 
 	DRM_DEBUG_KMS("[%d] %s\n", __LINE__, __func__);
 
-	ipu_plane_dpms(ipu_plane, DRM_MODE_DPMS_OFF);
+	if (ipu_plane->enabled)
+		ipu_plane_disable(ipu_plane);
 
 	ipu_plane_put_resources(ipu_plane);
 
-- 
2.1.0.rc1

regards
Philipp

[PATCH 2/2] imx-drm: ipuv3-plane: fix kernel Oops in ipu_dp_put()

[Shawn Guo]

On Tue, Aug 19, 2014 at 03:59:38PM +0200, Philipp Zabel wrote:
> > diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
> > index 6f393a11f44d..a79ae7731a03 100644
> > --- a/drivers/staging/imx-drm/ipuv3-plane.c
> > +++ b/drivers/staging/imx-drm/ipuv3-plane.c
> > @@ -274,15 +274,10 @@ static void ipu_plane_dpms(struct ipu_plane *ipu_plane, int mode)
> >  	if (enable == ipu_plane->enabled)
> >  		return;
> >  
> > -	if (enable) {
> > +	if (enable)
> >  		ipu_plane_enable(ipu_plane);
> > -	} else {
> > +	else
> >  		ipu_plane_disable(ipu_plane);
> > -
> > -		ipu_idmac_put(ipu_plane->ipu_ch);
> > -		ipu_dmfc_put(ipu_plane->dmfc);
> > -		ipu_dp_put(ipu_plane->dp);
> > -	}
> >  }
> >  
> >  /*
> 
> we could then remove ipu_plane_dpms completely:

Yeah, you're right, Philipp.  I will fold your code change below into my
v2 of the patch.  Thanks.

Shawn

> 
> ---
>  drivers/staging/imx-drm/ipuv3-plane.c | 23 ++++-------------------
>  1 file changed, 4 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
> index b2d1bb2..6987e16 100644
> --- a/drivers/staging/imx-drm/ipuv3-plane.c
> +++ b/drivers/staging/imx-drm/ipuv3-plane.c
> @@ -290,23 +290,6 @@ void ipu_plane_disable(struct ipu_plane *ipu_plane)
>  		ipu_dp_disable(ipu_plane->ipu);
>  }
>  
> -static void ipu_plane_dpms(struct ipu_plane *ipu_plane, int mode)
> -{
> -	bool enable;
> -
> -	DRM_DEBUG_KMS("mode = %d", mode);
> -
> -	enable = (mode == DRM_MODE_DPMS_ON);
> -
> -	if (enable == ipu_plane->enabled)
> -		return;
> -
> -	if (enable)
> -		ipu_plane_enable(ipu_plane);
> -	else
> -		ipu_plane_disable(ipu_plane);
> -}
> -
>  /*
>   * drm_plane API
>   */
> @@ -340,7 +323,8 @@ static int ipu_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
>  				plane->crtc, crtc);
>  	plane->crtc = crtc;
>  
> -	ipu_plane_dpms(ipu_plane, DRM_MODE_DPMS_ON);
> +	if (!ipu_plane->enabled)
> +		ipu_plane_enable(ipu_plane);
>  
>  	return 0;
>  }
> @@ -351,7 +335,8 @@ static int ipu_disable_plane(struct drm_plane *plane)
>  
>  	DRM_DEBUG_KMS("[%d] %s\n", __LINE__, __func__);
>  
> -	ipu_plane_dpms(ipu_plane, DRM_MODE_DPMS_OFF);
> +	if (ipu_plane->enabled)
> +		ipu_plane_disable(ipu_plane);
>  
>  	ipu_plane_put_resources(ipu_plane);
>  
> -- 
> 2.1.0.rc1
> 
> regards
> Philipp
>