This is a resend of the changes, the bugs were identified and fixed one year ago, however the fixes are still not found in the mainline: http://dri-devel.freedesktop.narkive.com/cWNFTOZC/patch-v2-0-3-drm-fix-i2c-adapter-device-driver-user-counter of_find_i2c_adapter_by_node() call requires quite often missing put_device(), and i2c_put_adapter() releases a device locked by i2c_get_adapter() only. Below is a common error reproduction scenario as a result of the misusage described above, this is run on iMX6 platform 4.8.0-rc1 with HDMI and I2C bus drivers compiled as kernel modules for clarity after changing arch/arm/configs/imx_v6_v7_defconfig: -CONFIG_I2C_IMX=y +CONFIG_I2C_IMX=m -CONFIG_DRM_IMX_HDMI=y +CONFIG_DRM_IMX_HDMI=m root@imx6q:~# lsmod Not tainted dw_hdmi_ahb_audio 4082 0 - Live 0xbf02c000 dw_hdmi_imx 3498 0 - Live 0xbf00d000 dw_hdmi 16398 2 dw_hdmi_ahb_audio,dw_hdmi_imx, Live 0xbf004000 i2c_imx 16687 0 - Live 0xbf017000 root@imx6q:~# rmmod dw_hdmi_imx root@imx6q:~# lsmod Not tainted dw_hdmi_ahb_audio 4082 0 - Live 0xbf02c000 dw_hdmi 16398 1 dw_hdmi_ahb_audio, Live 0xbf004000 i2c_imx 16687 -1 - Live 0xbf017000 ^^ root@imx6q:~# rmmod i2c_imx rmmod: ERROR: Module i2c_imx is in use To fix existing users of these interfaces use of_get_i2c_adapter_by_node() interface, which is similar to i2c_get_adapter() in sense that an I2C bus device driver found and locked by a user can be correctly unlocked by i2c_put_adapter() call. Changes from v2 to v2 resend: - none Changes from v1 to v2: - none, this series is a straightforward bugfix, v1 was a blend of I2C core changes, bugfixes and improvements Vladimir Zapolskiy (3): drm: dw_hdmi: use of_get_i2c_adapter_by_node interface drm: tilcdc: use of_get_i2c_adapter_by_node interface drm: tegra: use of_get_i2c_adapter_by_node interface drivers/gpu/drm/bridge/dw-hdmi.c | 14 +++++++++----- drivers/gpu/drm/tegra/output.c | 25 ++++++++++++++----------- drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 6 ++---- 3 files changed, 25 insertions(+), 20 deletions(-) -- 2.8.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
