From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: dri-devel@lists.freedesktop.org
Cc: John Stultz <john.stultz@linaro.org>,
lkml <linux-kernel@vger.kernel.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>
Subject: Re: [PATCH 2/5 v3] drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event()
Date: Mon, 16 Jan 2017 17:56:29 +0200 [thread overview]
Message-ID: <7359021.xs7IcXVQ9z@avalon> (raw)
In-Reply-To: <2543020.qSshgutoB3@avalon>
On Monday 16 Jan 2017 17:47:46 Laurent Pinchart wrote:
> Hi John,
>
> Thank you for the patch.
>
> On Tuesday 03 Jan 2017 11:41:39 John Stultz wrote:
> > In chasing down a previous issue with EDID probing from calling
> > drm_helper_hpd_irq_event() from irq context, Laurent noticed
> > that the DRM documentation suggests that
> > drm_kms_helper_hotplug_event() should be used instead.
> >
> > Thus this patch replaces drm_helper_hpd_irq_event() with
> > drm_kms_helper_hotplug_event(), which requires we update the
> > connector.status entry and only call _hotplug_event() when the
> > status changes.
> >
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Archit Taneja <architt@codeaurora.org>
> > Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > Cc: Lars-Peter Clausen <lars@metafoo.de>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: dri-devel@lists.freedesktop.org
> > Signed-off-by: John Stultz <john.stultz@linaro.org>
> > ---
> > v3: Update connector.status value and only call __hotplug_event()
> >
> > when that status changes, as suggested by Laurent.
> >
> > drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 16 +++++++++++++++-
> > 1 file changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 4fcea44..d93d66f
> > 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > @@ -405,8 +405,22 @@ static bool adv7511_hpd(struct adv7511 *adv7511)
> >
> > static void adv7511_hpd_work(struct work_struct *work)
> > {
> >
> > struct adv7511 *adv7511 = container_of(work, struct adv7511,
>
> hpd_work);
>
> > + enum drm_connector_status status;
> > + unsigned int val;
> > + int ret;
> > +
> > + ret = regmap_read(adv7511->regmap, ADV7511_REG_STATUS, &val);
> > + if (ret < 0)
> > + status = connector_status_disconnected;
> > + else if (val & ADV7511_STATUS_HPD)
> > + status = connector_status_connected;
> > + else
> > + status = connector_status_disconnected;
> > +
> > + if (adv7511->connector.status != status)
> > + drm_kms_helper_hotplug_event(adv7511->connector.dev);
> >
> > - drm_helper_hpd_irq_event(adv7511->connector.dev);
> > + adv7511->connector.status = status;
>
> Shouldn't you update the status before calling
> drm_kms_helper_hotplug_event() ? Doing it after not only creates a small
> race condition as
> drm_kms_helper_hotplug_event() sends an event to userspace that could result
> in an ioctl call to retrieve the status, but the status is also checked by
> drm_setup_crtcs() called by drm_fb_helper_hotplug_event().
With
if (adv7511->connector.status != status) {
adv7511->connector.status = status;
drm_kms_helper_hotplug_event(adv7511->connector.dev);
}
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > }
> >
> > static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2017-01-16 15:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-03 19:41 [PATCH 0/5 v3] adv7511 EDID probing improvements John Stultz
2017-01-03 19:41 ` [PATCH 1/5 v3] drm/bridge: adv7511: Use work_struct to defer hotplug handing to out of irq context John Stultz
2017-01-03 19:41 ` [PATCH 2/5 v3] drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event() John Stultz
2017-01-16 15:47 ` Laurent Pinchart
2017-01-16 15:56 ` Laurent Pinchart [this message]
2017-01-16 19:31 ` John Stultz
2017-01-03 19:41 ` [PATCH 3/5 v3] drm/bridge: adv7511: Enable HPD interrupts to support hotplug and improve monitor detection John Stultz
2017-01-03 19:41 ` [PATCH 4/5 v3] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally John Stultz
2017-01-16 15:50 ` Laurent Pinchart
2017-01-03 19:41 ` [PATCH 5/5 v3] drm/bridge: adv7511: Reuse __adv7511_power_on/off() when probing EDID John Stultz
2017-01-16 16:03 ` Laurent Pinchart
2017-01-16 20:14 ` John Stultz
2017-01-16 22:25 ` Laurent Pinchart
2017-01-16 23:16 ` [RFC][PATCH] drm/bridge: adv7511: Re-write the i2c address as it may have been lost John Stultz
2017-01-16 23:36 ` Laurent Pinchart
2017-01-16 23:39 ` John Stultz
2017-01-11 8:48 ` [PATCH 0/5 v3] adv7511 EDID probing improvements Archit Taneja
2017-01-12 0:06 ` John Stultz
2017-01-12 4:22 ` Archit Taneja
2017-01-16 15:57 ` Laurent Pinchart
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