Hi,
On Mon, Feb 24, 2025 at 12:14 AM Damon Ding <damon.ding@xxxxxxxxxxxxxx> wrote:
>
> The main modification is moving the DP AUX initialization from function
> analogix_dp_bind() to analogix_dp_probe(). In order to get the EDID of
> eDP panel during probing, it is also needed to advance PM operations to
> ensure that eDP controller and phy are prepared for AUX transmission.
>
> Additionally, add support for &drm_dp_aux.wait_hpd_asserted() to help
> confirm the HPD state before doing AUX transfers.
Maybe move the addition of the analogix_dpaux_wait_hpd_asserted() to a
separate patch?
> Signed-off-by: Damon Ding <damon.ding@xxxxxxxxxxxxxx>
>
> ---
>
> Changes in v4:
> - Use done_probing() to call drm_of_find_panel_or_bridge() and
> component_add() when getting panel from the DP AUX bus
>
> Changes in v5:
> - Advance PM operations to make eDP AUX work well
>
> Changes in v6:
> - Use devm_pm_runtime_enable() instead of devm_add_action_or_reset()
> - Add a new function analogix_dp_remove() to ensure symmetry for PM
> operations
>
> Changes in v7:
> - Fix the misspelling of word 'operations' in commit message
> - Remove the check related to CONFIG_PM
> - Remove the unnecessary call to pm_runtime_dont_use_autosuspend() if
> devm_pm_runtime_enable() fails
> - Remove unnecessary function analogix_dp_remove()
> - Add new function analogix_dpaux_wait_hpd_asserted()
> ---
> .../drm/bridge/analogix/analogix_dp_core.c | 37 ++++++++++++++-----
> 1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index a57e06d303a1..ff81c37dbe1d 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1548,6 +1548,22 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux,
> return ret;
> }
>
> +static int analogix_dpaux_wait_hpd_asserted(struct drm_dp_aux *aux, unsigned long wait_us)
> +{
> + struct analogix_dp_device *dp = to_dp(aux);
> + int val;
> + int ret;
> +
> + pm_runtime_get_sync(dp->dev);
> +
> + ret = readx_poll_timeout(analogix_dp_detect_hpd, dp, val, !val, wait_us / 100, wait_us);
More than happy if someone else wants to overrule me, but it seems
weird that you're looping over a function that already has a loop.
Shouldn't you be calling analogix_dp_get_plug_in_status() directly?
...and if "dp->force_hpd" you probably shouldn't be polling at all. If
HPD is not hooked up I think we decided in sn65dsi86 that we should
just sleep for the maximum time (choosing a conservative value if told
to wait forever).
Aside from that and the idea of moving
analogix_dpaux_wait_hpd_asserted() to a separate patch this looks good
to me.
-Doug
