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Date: Fri, 4 Dec 2015 09:53:52 +0100
From: Christian König <christian.koenig@....com>
To: <cpaul@...hat.com>, Alex Deucher <alexander.deucher@....com>,
David Airlie <airlied@...ux.ie>,
<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
CC: Jerome Glisse <jglisse@...hat.com>,
Benjamin Tissoires <benjamin.tissoires@...hat.com>
Subject: Re: [PATCH v2] drm/radeon: Retry DDC probing on DVI on failure if we
got an HPD interrupt
On 04.12.2015 00:26, cpaul@...hat.com wrote:
> From: Lyude <cpaul@...hat.com>
>
> HPD signals on DVI ports can be fired off before the pins required for
> DDC probing actually make contact, due to the pins for HPD making
> contact first. This results in a HPD signal being asserted but DDC
> probing failing, resulting in hotplugging occasionally failing.
>
> This is somewhat rare on most cards (depending on what angle you plug
> the DVI connector in), but on some cards it happens constantly. The
> Radeon R5 on the machine used for testing this patch for instance, runs
> into this issue just about every time I try to hotplug a DVI monitor and
> as a result hotplugging almost never works.
>
> Rescheduling the hotplug work for a second when we run into an HPD
> signal with a failing DDC probe usually gives enough time for the rest
> of the connector's pins to make contact, and fixes this issue.
>
> Signed-off-by: Lyude <cpaul@...hat.com>
I find a second a bit long, but if it works so what?
Looks sane enough to me, patch is Reviewed-by: Christian König
<christian.koenig@....com>
> ---
> Sending this version of the patch because Jerome says this will probably be the
> least controversial of the potential fixes. Instead of sending userspace tons of
> hotplug events, we just reschedule the hotplug work.
>
> drivers/gpu/drm/radeon/cik.c | 2 +-
> drivers/gpu/drm/radeon/evergreen.c | 2 +-
> drivers/gpu/drm/radeon/r100.c | 2 +-
> drivers/gpu/drm/radeon/r600.c | 2 +-
> drivers/gpu/drm/radeon/radeon.h | 2 +-
> drivers/gpu/drm/radeon/radeon_connectors.c | 21 ++++++++++++++++++++-
> drivers/gpu/drm/radeon/radeon_irq_kms.c | 8 ++++----
> drivers/gpu/drm/radeon/radeon_mode.h | 1 +
> drivers/gpu/drm/radeon/rs600.c | 2 +-
> drivers/gpu/drm/radeon/si.c | 2 +-
> 10 files changed, 32 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
> index 248953d..6801a0c 100644
> --- a/drivers/gpu/drm/radeon/cik.c
> +++ b/drivers/gpu/drm/radeon/cik.c
> @@ -8472,7 +8472,7 @@ restart_ih:
> if (queue_dp)
> schedule_work(&rdev->dp_work);
> if (queue_hotplug)
> - schedule_work(&rdev->hotplug_work);
> + schedule_delayed_work(&rdev->hotplug_work, 0);
> if (queue_reset) {
> rdev->needs_reset = true;
> wake_up_all(&rdev->fence_queue);
> diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
> index 0acde19..f8e4986 100644
> --- a/drivers/gpu/drm/radeon/evergreen.c
> +++ b/drivers/gpu/drm/radeon/evergreen.c
> @@ -5368,7 +5368,7 @@ restart_ih:
> if (queue_dp)
> schedule_work(&rdev->dp_work);
> if (queue_hotplug)
> - schedule_work(&rdev->hotplug_work);
> + schedule_delayed_work(&rdev->hotplug_work, 0);
> if (queue_hdmi)
> schedule_work(&rdev->audio_work);
> if (queue_thermal && rdev->pm.dpm_enabled)
> diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
> index 238b13f..2df3c86 100644
> --- a/drivers/gpu/drm/radeon/r100.c
> +++ b/drivers/gpu/drm/radeon/r100.c
> @@ -806,7 +806,7 @@ int r100_irq_process(struct radeon_device *rdev)
> status = r100_irq_ack(rdev);
> }
> if (queue_hotplug)
> - schedule_work(&rdev->hotplug_work);
> + schedule_delayed_work(&rdev->hotplug_work, 0);
> if (rdev->msi_enabled) {
> switch (rdev->family) {
> case CHIP_RS400:
> diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
> index 4ea5b10..cc2fdf0 100644
> --- a/drivers/gpu/drm/radeon/r600.c
> +++ b/drivers/gpu/drm/radeon/r600.c
> @@ -4276,7 +4276,7 @@ restart_ih:
> WREG32(IH_RB_RPTR, rptr);
> }
> if (queue_hotplug)
> - schedule_work(&rdev->hotplug_work);
> + schedule_delayed_work(&rdev->hotplug_work, 0);
> if (queue_hdmi)
> schedule_work(&rdev->audio_work);
> if (queue_thermal && rdev->pm.dpm_enabled)
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index b6cbd81..87db649 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -2414,7 +2414,7 @@ struct radeon_device {
> struct r600_ih ih; /* r6/700 interrupt ring */
> struct radeon_rlc rlc;
> struct radeon_mec mec;
> - struct work_struct hotplug_work;
> + struct delayed_work hotplug_work;
> struct work_struct dp_work;
> struct work_struct audio_work;
> int num_crtc; /* number of crtcs */
> diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
> index 5a2cafb..340f3f5 100644
> --- a/drivers/gpu/drm/radeon/radeon_connectors.c
> +++ b/drivers/gpu/drm/radeon/radeon_connectors.c
> @@ -1234,13 +1234,32 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
> if (r < 0)
> return connector_status_disconnected;
>
> + if (radeon_connector->detected_hpd_without_ddc) {
> + force = true;
> + radeon_connector->detected_hpd_without_ddc = false;
> + }
> +
> if (!force && radeon_check_hpd_status_unchanged(connector)) {
> ret = connector->status;
> goto exit;
> }
>
> - if (radeon_connector->ddc_bus)
> + if (radeon_connector->ddc_bus) {
> dret = radeon_ddc_probe(radeon_connector, false);
> +
> + /* Sometimes the pins required for the DDC probe on DVI
> + * connectors don't make contact at the same time that the ones
> + * for HPD do. If the DDC probe fails even though we had an HPD
> + * signal, try again later */
> + if (!dret && !force &&
> + connector->status != connector_status_connected) {
> + DRM_DEBUG_KMS("hpd detected without ddc, retrying in 1 second\n");
> + radeon_connector->detected_hpd_without_ddc = true;
> + schedule_delayed_work(&rdev->hotplug_work,
> + msecs_to_jiffies(1000));
> + goto exit;
> + }
> + }
> if (dret) {
> radeon_connector->detected_by_load = false;
> radeon_connector_free_edid(connector);
> diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c
> index 171d3e4..979f3bf 100644
> --- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
> +++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
> @@ -74,7 +74,7 @@ irqreturn_t radeon_driver_irq_handler_kms(int irq, void *arg)
> static void radeon_hotplug_work_func(struct work_struct *work)
> {
> struct radeon_device *rdev = container_of(work, struct radeon_device,
> - hotplug_work);
> + hotplug_work.work);
> struct drm_device *dev = rdev->ddev;
> struct drm_mode_config *mode_config = &dev->mode_config;
> struct drm_connector *connector;
> @@ -302,7 +302,7 @@ int radeon_irq_kms_init(struct radeon_device *rdev)
> }
> }
>
> - INIT_WORK(&rdev->hotplug_work, radeon_hotplug_work_func);
> + INIT_DELAYED_WORK(&rdev->hotplug_work, radeon_hotplug_work_func);
> INIT_WORK(&rdev->dp_work, radeon_dp_work_func);
> INIT_WORK(&rdev->audio_work, r600_audio_update_hdmi);
>
> @@ -310,7 +310,7 @@ int radeon_irq_kms_init(struct radeon_device *rdev)
> r = drm_irq_install(rdev->ddev, rdev->ddev->pdev->irq);
> if (r) {
> rdev->irq.installed = false;
> - flush_work(&rdev->hotplug_work);
> + flush_delayed_work(&rdev->hotplug_work);
> return r;
> }
>
> @@ -333,7 +333,7 @@ void radeon_irq_kms_fini(struct radeon_device *rdev)
> rdev->irq.installed = false;
> if (rdev->msi_enabled)
> pci_disable_msi(rdev->pdev);
> - flush_work(&rdev->hotplug_work);
> + flush_delayed_work(&rdev->hotplug_work);
> }
> }
>
> diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
> index 457b026..0aeb3ee 100644
> --- a/drivers/gpu/drm/radeon/radeon_mode.h
> +++ b/drivers/gpu/drm/radeon/radeon_mode.h
> @@ -553,6 +553,7 @@ struct radeon_connector {
> void *con_priv;
> bool dac_load_detect;
> bool detected_by_load; /* if the connection status was determined by load */
> + bool detected_hpd_without_ddc; /* if an HPD signal was detected on DVI, but ddc probing failed */
> uint16_t connector_object_id;
> struct radeon_hpd hpd;
> struct radeon_router router;
> diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c
> index 97a9048..6244f4e 100644
> --- a/drivers/gpu/drm/radeon/rs600.c
> +++ b/drivers/gpu/drm/radeon/rs600.c
> @@ -813,7 +813,7 @@ int rs600_irq_process(struct radeon_device *rdev)
> status = rs600_irq_ack(rdev);
> }
> if (queue_hotplug)
> - schedule_work(&rdev->hotplug_work);
> + schedule_delayed_work(&rdev->hotplug_work, 0);
> if (queue_hdmi)
> schedule_work(&rdev->audio_work);
> if (rdev->msi_enabled) {
> diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
> index 07037e3..fb1a7ec 100644
> --- a/drivers/gpu/drm/radeon/si.c
> +++ b/drivers/gpu/drm/radeon/si.c
> @@ -6848,7 +6848,7 @@ restart_ih:
> if (queue_dp)
> schedule_work(&rdev->dp_work);
> if (queue_hotplug)
> - schedule_work(&rdev->hotplug_work);
> + schedule_delayed_work(&rdev->hotplug_work, 0);
> if (queue_thermal && rdev->pm.dpm_enabled)
> schedule_work(&rdev->pm.dpm.thermal.work);
> rdev->ih.rptr = rptr;
--
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