Re: [PATCH 2/2] drm/vc4: hdmi: Convert to gpiod

[Nathan Chancellor]

On Fri, Jul 02, 2021 at 03:16:46PM +0200, Maxime Ripard wrote:
> Hi Nathan,
> 
> On Thu, Jul 01, 2021 at 08:29:34PM -0700, Nathan Chancellor wrote:
> > On Mon, May 24, 2021 at 03:18:52PM +0200, Maxime Ripard wrote:
> > > The new gpiod interface takes care of parsing the GPIO flags and to
> > > return the logical value when accessing an active-low GPIO, so switching
> > > to it simplifies a lot the driver.
> > > 
> > > Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/vc4/vc4_hdmi.c | 24 +++++++-----------------
> > >  drivers/gpu/drm/vc4/vc4_hdmi.h |  3 +--
> > >  2 files changed, 8 insertions(+), 19 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > > index ccc6c8079dc6..34622c59f6a7 100644
> > > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> > > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > > @@ -159,10 +159,9 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
> > >  	struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
> > >  	bool connected = false;
> > >  
> > > -	if (vc4_hdmi->hpd_gpio) {
> > > -		if (gpio_get_value_cansleep(vc4_hdmi->hpd_gpio) ^
> > > -		    vc4_hdmi->hpd_active_low)
> > > -			connected = true;
> > > +	if (vc4_hdmi->hpd_gpio &&
> > > +	    gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio)) {
> > > +		connected = true;
> > >  	} else if (drm_probe_ddc(vc4_hdmi->ddc)) {
> > >  		connected = true;
> > >  	} else if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED) {
> > > @@ -1993,7 +1992,6 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
> > >  	struct vc4_hdmi *vc4_hdmi;
> > >  	struct drm_encoder *encoder;
> > >  	struct device_node *ddc_node;
> > > -	u32 value;
> > >  	int ret;
> > >  
> > >  	vc4_hdmi = devm_kzalloc(dev, sizeof(*vc4_hdmi), GFP_KERNEL);
> > > @@ -2031,18 +2029,10 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
> > >  	/* Only use the GPIO HPD pin if present in the DT, otherwise
> > >  	 * we'll use the HDMI core's register.
> > >  	 */
> > > -	if (of_find_property(dev->of_node, "hpd-gpios", &value)) {
> > > -		enum of_gpio_flags hpd_gpio_flags;
> > > -
> > > -		vc4_hdmi->hpd_gpio = of_get_named_gpio_flags(dev->of_node,
> > > -							     "hpd-gpios", 0,
> > > -							     &hpd_gpio_flags);
> > > -		if (vc4_hdmi->hpd_gpio < 0) {
> > > -			ret = vc4_hdmi->hpd_gpio;
> > > -			goto err_put_ddc;
> > > -		}
> > > -
> > > -		vc4_hdmi->hpd_active_low = hpd_gpio_flags & OF_GPIO_ACTIVE_LOW;
> > > +	vc4_hdmi->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
> > > +	if (IS_ERR(vc4_hdmi->hpd_gpio)) {
> > > +		ret = PTR_ERR(vc4_hdmi->hpd_gpio);
> > > +		goto err_put_ddc;
> > >  	}
> > >  
> > >  	vc4_hdmi->disable_wifi_frequencies =
> > > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
> > > index 060bcaefbeb5..2688a55461d6 100644
> > > --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
> > > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
> > > @@ -146,8 +146,7 @@ struct vc4_hdmi {
> > >  	/* VC5 Only */
> > >  	void __iomem *rm_regs;
> > >  
> > > -	int hpd_gpio;
> > > -	bool hpd_active_low;
> > > +	struct gpio_desc *hpd_gpio;
> > >  
> > >  	/*
> > >  	 * On some systems (like the RPi4), some modes are in the same
> > > -- 
> > > 2.31.1
> > 
> > This patch as commit 6800234ceee0 ("drm/vc4: hdmi: Convert to gpiod")
> > causes my Raspberry Pi 3 to lock up shortly after boot in combination
> > with commit 411efa18e4b0 ("drm/vc4: hdmi: Move the HSM clock enable to
> > runtime_pm"). The serial console and ssh are completely unresponsive and
> > I do not see any messages in dmesg with "debug ignore_loglevel". The
> > device is running with a 32-bit kernel (multi_v7_defconfig) with 32-bit
> > userspace. If there is any further information that I can provide,
> > please let me know.
> 
> Thanks for reporting this. The same bug has been reported on wednesday
> on the RPi repo here:
> https://github.com/raspberrypi/linux/pull/4418
> 
> More specifically, this commit should fix it:
> https://github.com/raspberrypi/linux/pull/4418/commits/6d404373c20a794da3d6a7b4f1373903183bb5d0
> 
> Even though it's based on the 5.10 kernel, it should apply without any
> warning on a mainline tree. Let me know if it fixes your issue too

Thank you for the links and the quick reply. Unfortunately, I applied
this patch on top of commit d6b63b5b7d7f ("Merge tag 'sound-5.14-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound") in mainline,
which does reproduce this issue still and it did not fix the issue. In
fact, it did not even get to the raspberrypi login prompt before it
locked up, yet again without any real output in the serial console
except for maybe this message?

[    7.582480] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])

If there is anything further that I can provide or test, please let me
know!

Cheers,
Nathan