Messages in this thread | | | Subject | Re: [RFC][PATCH] drm: adv7511/33: Fix adv7511_cec_init() failure handling | From | Archit Taneja <> | Date | Sun, 26 Nov 2017 18:26:06 +0530 |
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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; > #else > - 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; > >
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