Hi Neil,
On 2024-06-24 11:56, neil.armstr...@linaro.org wrote:
> On 24/06/2024 11:41, Jonas Karlman wrote:
>> Hi Neil,
>>
>> On 2024-06-24 11:23, Neil Armstrong wrote:
>>> On 11/06/2024 17:50, Jonas Karlman wrote:
>>>> Change to only call poweron/poweroff from atomic_enable/atomic_disable
>>>> ops instead of trying to keep a bridge_is_on state and poweron/off in
>>>> the hotplug irq handler.
>>>>
>>>> A benefit of this is that drm mode_config mutex is always held at
>>>> poweron/off, something that may reduce the need for our own mutex.
>>>>
>>>> Signed-off-by: Jonas Karlman <jo...@kwiboo.se>
>>>> ---
>>>> drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 33 ++---------------------
>>>> 1 file changed, 2 insertions(+), 31 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> index 9f2bc932c371..34bc6f4754b8 100644
>>>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> @@ -172,7 +172,6 @@ struct dw_hdmi {
>>>> enum drm_connector_force force; /* mutex-protected force state
>>>> */
>>>> struct drm_connector *curr_conn;/* current connector (only
>>>> valid when !disabled) */
>>>> bool disabled; /* DRM has disabled our bridge
>>>> */
>>>> - bool bridge_is_on; /* indicates the bridge is on */
>>>> bool rxsense; /* rxsense state */
>>>> u8 phy_mask; /* desired phy int mask
>>>> settings */
>>>> u8 mc_clkdis; /* clock disable register */
>>>> @@ -2383,8 +2382,6 @@ static void initialize_hdmi_ih_mutes(struct dw_hdmi
>>>> *hdmi)
>>>>
>>>> static void dw_hdmi_poweron(struct dw_hdmi *hdmi)
>>>> {
>>>> - hdmi->bridge_is_on = true;
>>>> -
>>>> /*
>>>> * The curr_conn field is guaranteed to be valid here, as this
>>>> function
>>>> * is only be called when !hdmi->disabled.
>>>> @@ -2398,30 +2395,6 @@ static void dw_hdmi_poweroff(struct dw_hdmi *hdmi)
>>>> hdmi->phy.ops->disable(hdmi, hdmi->phy.data);
>>>> hdmi->phy.enabled = false;
>>>> }
>>>> -
>>>> - hdmi->bridge_is_on = false;
>>>> -}
>>>> -
>>>> -static void dw_hdmi_update_power(struct dw_hdmi *hdmi)
>>>> -{
>>>> - int force = hdmi->force;
>>>> -
>>>> - if (hdmi->disabled) {
>>>> - force = DRM_FORCE_OFF;
>>>> - } else if (force == DRM_FORCE_UNSPECIFIED) {
>>>> - if (hdmi->rxsense)
>>>> - force = DRM_FORCE_ON;
>>>> - else
>>>> - force = DRM_FORCE_OFF;
>>>> - }
>>>
>>> This means we always poweron the bridge even if rxsense is false ?
>>
>> If I follow the logic there should not be any difference, beside that
>> power on now only happen in atomic_enable instead of sometime in irq
>> handler.
>>
>> hdmi->rxsense is set to true based on hpd in dw_hdmi_setup_rx_sense().
>> For both meson and dw-hdmi this means HPD=1 and not rxsense=1.
>
> Yeah I know, I was worried for other platforms using rxsense
>From what I can find only dw-hdmi.c and dw_hdmi_meson.c are caller of
dw_hdmi_setup_rx_sense(). For meson the same value is passed for both
hpd and rx_sense, everyone else hpd = HPD and rx_sense = RX_SENSE status.
My understanding and testing based on Rockchip has shown that rx_sense
has no significant impact before and after this change.
>
>>
>> drm core will call the force/detect ops and enable/disable based on
>> forced/HPD state, so I am not expecting any difference in how this
>> currently works.
>>
>> This change to only poweron/setup in atomic_enable should also fix
>> issues/situations where dw-hdmi was poweron too early during bootup in
>> irq handler, before the drm driver was fully probed.
I may have been wrong here, there is a check for disabled here so it
should not have setup() before atomic_enable().
Still we should ensure configure happen in atomic_enable(). The
hpd_irq_event/hpd_notify calls will trigger a detect() and signal core
if the bridge should be enabled/disabled when connector status changes.
>
> Hmm, but I thought the code wouldn't poweron the bridge is rxsense was 0
> even if a mode was set, this won't work like this anymore right ?
This is what I thought was happening, and the comment in code seem to
indicate that. However, the code only seem to care about HPD=1 status to
poweron() and possible both HPD=0 + RXSENSE=0 to poweroff().
To make matter more complex core also mainly care about detect() status
and most/all related drivers seem to only use the the HPD status.
So I would say that there should not be any changes in impact of the
rxsense signal.
Will also send a new patch in a v2 for dw_hdmi_irq() that may be related:
- if (phy_stat & HDMI_PHY_HPD)
+ if ((intr_stat & HDMI_IH_PHY_STAT0_HPD) &&
+ (phy_stat & HDMI_PHY_HPD))
status = connector_status_connected;
or there may be a status_connected event triggered when rxsense goes
from 1 to 0 and a second one with status_disconnected shortly after when
hpd goes from 1 to 0 when the cable is removed.
Regards,
Jonas
>
> Neil
>
>>
>> Regards,
>> Jonas
>>
>>>
>>> Neil
>>>
>>>> -
>>>> - if (force == DRM_FORCE_OFF) {
>>>> - if (hdmi->bridge_is_on)
>>>> - dw_hdmi_poweroff(hdmi);
>>>> - } else {
>>>> - if (!hdmi->bridge_is_on)
>>>> - dw_hdmi_poweron(hdmi);
>>>> - }
>>>> }
>>>>
>>>> /*
>>>> @@ -2546,7 +2519,6 @@ static void dw_hdmi_connector_force(struct
>>>> drm_connector *connector)
>>>>
>>>> mutex_lock(&hdmi->mutex);
>>>> hdmi->force = connector->force;
>>>> - dw_hdmi_update_power(hdmi);
>>>> dw_hdmi_update_phy_mask(hdmi);
>>>> mutex_unlock(&hdmi->mutex);
>>>> }
>>>> @@ -2955,7 +2927,7 @@ static void dw_hdmi_bridge_atomic_disable(struct
>>>> drm_bridge *bridge,
>>>> mutex_lock(&hdmi->mutex);
>>>> hdmi->disabled = true;
>>>> hdmi->curr_conn = NULL;
>>>> - dw_hdmi_update_power(hdmi);
>>>> + dw_hdmi_poweroff(hdmi);
>>>> dw_hdmi_update_phy_mask(hdmi);
>>>> handle_plugged_change(hdmi, false);
>>>> mutex_unlock(&hdmi->mutex);
>>>> @@ -2974,7 +2946,7 @@ static void dw_hdmi_bridge_atomic_enable(struct
>>>> drm_bridge *bridge,
>>>> mutex_lock(&hdmi->mutex);
>>>> hdmi->disabled = false;
>>>> hdmi->curr_conn = connector;
>>>> - dw_hdmi_update_power(hdmi);
>>>> + dw_hdmi_poweron(hdmi);
>>>> dw_hdmi_update_phy_mask(hdmi);
>>>> handle_plugged_change(hdmi, true);
>>>> mutex_unlock(&hdmi->mutex);
>>>> @@ -3073,7 +3045,6 @@ void dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi,
>>>> bool hpd, bool rx_sense)
>>>> if (hpd)
>>>> hdmi->rxsense = true;
>>>>
>>>> - dw_hdmi_update_power(hdmi);
>>>> dw_hdmi_update_phy_mask(hdmi);
>>>> }
>>>> mutex_unlock(&hdmi->mutex);
>>>
>>
>
