Hi,
On 11/17/2017 04:29 AM, John Stultz wrote:
From: Arnd Bergmann arnd@arndb.de
An otherwise correct cleanup patch from Dan Carpenter turned a broken failure handling from a feature patch by Hans Verkuil into a kernel Oops, so bisection points to commit 7af35b0addbc ("drm/kirin: Checking for IS_ERR() instead of NULL") rather than 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support").
I've managed to piece together several partial problems, though I'm still struggling with the bigger picture:
adv7511_probe() registers a drm_bridge structure that was allocated with devm_kzalloc(). It calls adv7511_cec_init(), which fails for an unknown reason, which in turn triggers the registered structure to be removed.
Elsewhere, kirin_drm_platform_probe() gets called, which calls of_graph_get_remote_node(), and that returns NULL. Before Dan's patch we would go on with a NULL pointer here and register that, now kirin_drm_platform_probe() fails with -ENODEV.
In a third driver, dsi_parse_dt() calls drm_of_find_panel_or_bridge(), which after not finding a panel goes on to call of_drm_find_bridge(), and that crashes due to the earlier list corruption.
This addresses the first issue by making sure that adv7511_probe() does not completely fail when the adv7511_cec_init() function fails, and instead we just disable the CEC feature. This avoids having the driver entirely fail to load if just the CEC initialization fails.
Reported-by: Naresh Kamboju naresh.kamboju@linaro.org Cc: Xinliang Liu xinliang.liu@linaro.org Cc: Dan Carpenter dan.carpenter@oracle.com Cc: Sean Paul seanpaul@chromium.org Cc: Hans Verkuil hans.verkuil@cisco.com Cc: Archit Taneja architt@codeaurora.org Link: https://bugs.linaro.org/show_bug.cgi?id=3345 Link: https://lkft.validation.linaro.org/scheduler/job/48017#L3551 Fixes: 7af35b0addbc ("drm/kirin: Checking for IS_ERR() instead of NULL") Fixes: 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support") Signed-off-by: Arnd Bergmann arnd@arndb.de [jstultz: Reworked so when adv7511_cec_init() fails, we disable the feature instead of disabling the entire driver, which causes graphics to not funciton] Signed-off-by: John Stultz john.stultz@linaro.org
Just wanted to send out my rework of Arnd's patch here. Feedback would be welcome.
thanks -john
drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 0e14f15..939c3b9 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -1203,12 +1203,12 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
#ifdef CONFIG_DRM_I2C_ADV7511_CEC ret = adv7511_cec_init(dev, adv7511, offset);
- if (ret)
goto err_unregister_cec;- regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset,
ADV7511_CEC_CTRL_POWER_DOWN);
- ret = 1; #endif
- if (ret)
regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset,ADV7511_CEC_CTRL_POWER_DOWN);
This would force CEC to be powered off even if adv7511_cec_init() returned 0, right? We wouldn't want that if we want to use CEC on a platform that supports it.
Do we know why the call to adv7511_cec_init() is failing on the Hikey board? If it's because there isn't a "cec" clock specified in DT, it's not really a fatal error, it just means that the platform hasn't been set up to support CEC. In that case, we should just power down the CEC block. So, if adv7511_cec_init() would return a -ENOENT, which we could use as a hint to power down CEC. So, maybe something like this?:
#ifdef CONFIG_DRM_I2C_ADV7511_CEC ret = adv7511_cec_init(dev, adv7511, offset); if (ret && ret != -ENOENT) goto err_unregister_cec; #endif if (ret) regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset, ADV7511_CEC_CTRL_POWER_DOWN);
Apart from this, we should also move adv7511_cec_init() up in the probe so that it's called before the drm_bridge is registered.
Thanks, Archit
return 0;