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Message-ID: <87cys81wk5.fsf@intel.com>
Date: Tue, 05 Mar 2024 18:18:50 +0200
From: Jani Nikula <jani.nikula@...ux.intel.com>
To: Alvin Šipraga <alvin@...s.dk>, Andrzej Hajda
<andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss
<rfoss@...nel.org>, Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec
<jernej.skrabec@...il.com>, David Airlie <airlied@...il.com>, Daniel
Vetter <daniel@...ll.ch>, Hans Verkuil <hverkuil-cisco@...all.nl>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, Alvin
Šipraga <alsi@...g-olufsen.dk>
Subject: Re: [PATCH v3 2/2] drm/bridge: adv7511: get edid in hpd_work to
update CEC phys address
On Mon, 19 Feb 2024, Alvin Šipraga <alvin@...s.dk> wrote:
> From: Alvin Šipraga <alsi@...g-olufsen.dk>
>
> The adv7511 driver is solely responsible for setting the physical
> address of its CEC adapter. To do this, it must read the EDID. However,
> EDID is only read when either the drm_bridge_funcs :: get_edid or
> drm_connector_helper_funcs :: get_modes ops are called. Without loss of
> generality, it cannot be assumed that these ops are called when a sink
> gets attached. Therefore there exist scenarios in which the CEC physical
> address will be invalid (f.f.f.f), rendering the CEC adapter inoperable.
>
> Address this problem by always fetching the EDID in the HPD work when we
> detect a connection. The CEC physical address is set in the process.
> This is done by moving the EDID DRM helper into an internal helper
> function so that it can be cleanly called from an earlier section of
> the code. The EDID getter has not changed in practice.
>
> Reviewed-by: Robert Foss <rfoss@...nel.org>
> Signed-off-by: Alvin Šipraga <alsi@...g-olufsen.dk>
> ---
> drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 73 ++++++++++++++++++----------
> 1 file changed, 47 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> index 5ffc5904bd59..d823b372ff43 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -542,6 +542,36 @@ static int adv7511_get_edid_block(void *data, u8 *buf, unsigned int block,
> return 0;
> }
>
> +static struct edid *__adv7511_get_edid(struct adv7511 *adv7511,
> + struct drm_connector *connector)
> +{
> + struct edid *edid;
> +
> + /* Reading the EDID only works if the device is powered */
> + if (!adv7511->powered) {
> + unsigned int edid_i2c_addr =
> + (adv7511->i2c_edid->addr << 1);
> +
> + __adv7511_power_on(adv7511);
> +
> + /* Reset the EDID_I2C_ADDR register as it might be cleared */
> + regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR,
> + edid_i2c_addr);
> + }
> +
> + edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
> +
> + if (!adv7511->powered)
> + __adv7511_power_off(adv7511);
> +
> + adv7511_set_config_csc(adv7511, connector, adv7511->rgb,
> + drm_detect_hdmi_monitor(edid));
> +
> + cec_s_phys_addr_from_edid(adv7511->cec_adap, edid);
It really would be better to do drm_edid_read_custom(),
drm_edid_connector_update(), and cec_s_phys_addr() with the physical
address from connector->display_info.source_physical_address initialized
by drm_edid_connector_update().
The point is, cec_s_phys_addr_from_edid() has its own duplicate EDID
parsing, which is slightly different from drm_edid_connector_update()
and of course redundant.
BR,
Jani.
> +
> + return edid;
> +}
> +
> /* -----------------------------------------------------------------------------
> * Hotplug handling
> */
> @@ -595,8 +625,23 @@ static void adv7511_hpd_work(struct work_struct *work)
> adv7511->connector.status = status;
>
> if (adv7511->connector.dev) {
> - if (status == connector_status_disconnected)
> + if (status == connector_status_disconnected) {
> cec_phys_addr_invalidate(adv7511->cec_adap);
> + } else {
> + struct edid *edid;
> +
> + /*
> + * Get the updated EDID so that the CEC
> + * subsystem gets informed of any change in CEC
> + * address. The helper returns a newly allocated
> + * edid structure, so free it to prevent
> + * leakage.
> + */
> + edid = __adv7511_get_edid(adv7511,
> + &adv7511->connector);
> + kfree(edid);
> + }
> +
> drm_kms_helper_hotplug_event(adv7511->connector.dev);
> } else {
> drm_bridge_hpd_notify(&adv7511->bridge, status);
> @@ -611,31 +656,7 @@ static void adv7511_hpd_work(struct work_struct *work)
> static struct edid *adv7511_get_edid(struct adv7511 *adv7511,
> struct drm_connector *connector)
> {
> - struct edid *edid;
> -
> - /* Reading the EDID only works if the device is powered */
> - if (!adv7511->powered) {
> - unsigned int edid_i2c_addr =
> - (adv7511->i2c_edid->addr << 1);
> -
> - __adv7511_power_on(adv7511);
> -
> - /* Reset the EDID_I2C_ADDR register as it might be cleared */
> - regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR,
> - edid_i2c_addr);
> - }
> -
> - edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
> -
> - if (!adv7511->powered)
> - __adv7511_power_off(adv7511);
> -
> - adv7511_set_config_csc(adv7511, connector, adv7511->rgb,
> - drm_detect_hdmi_monitor(edid));
> -
> - cec_s_phys_addr_from_edid(adv7511->cec_adap, edid);
> -
> - return edid;
> + return __adv7511_get_edid(adv7511, connector);
> }
>
> static int adv7511_get_modes(struct adv7511 *adv7511,
--
Jani Nikula, Intel
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