On Thu, May 19, 2022 at 09:26:59AM -0700, Guillaume Ranquet wrote:
On Thu, 12 May 2022 09:44, Maxime Ripard maxime@cerno.tech wrote:
Hi,
On Wed, May 11, 2022 at 05:59:13AM -0700, Guillaume Ranquet wrote:
+#include <drm/drm_atomic_helper.h> +#include <drm/drm_bridge.h> +#include <drm/drm_crtc.h> +#include <drm/dp/drm_dp_helper.h> +#include <drm/drm_edid.h> +#include <drm/drm_of.h> +#include <drm/drm_panel.h> +#include <drm/drm_print.h> +#include <drm/drm_probe_helper.h> +#include <linux/arm-smccc.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/mfd/syscon.h> +#include <linux/nvmem-consumer.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_platform.h> +#include <linux/phy/phy.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/regmap.h> +#include <sound/hdmi-codec.h> +#include <video/videomode.h>
+#include "mtk_dp_reg.h"
+#define MTK_DP_AUX_WAIT_REPLY_COUNT 20 +#define MTK_DP_CHECK_SINK_CAP_TIMEOUT_COUNT 3
+//TODO: platform/device data or dts?
DTS :)
It's probably going to be a platform_data struct for v10... If I have time, I'll change it to a dts property for v10.
I can't really imagine a case where we would need platform_data nowadays. If you have a device tree, then it should be part of the binding.
What issue would you like to address by using a platform_data?
Ok, I'll migrate to dt then. I didn't realize platform_data were depreciated.
Angelo wants the MAX_LINRATE and MAX_LANES defines to be configurable. I imagined platform_data would be more appropriate as (per my understanding) the limitation is associated with a specific SoC.
The entire device tree is nothing but a collection of data associated to a specific SoC though :)
+static struct edid *mtk_dp_get_edid(struct drm_bridge *bridge,
struct drm_connector *connector)+{
- struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
- bool enabled = mtk_dp->enabled;
- struct edid *new_edid = NULL;
- if (!enabled)
drm_bridge_chain_pre_enable(bridge);- drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER, DP_SET_POWER_D0);
- usleep_range(2000, 5000);
- if (mtk_dp_plug_state(mtk_dp))
new_edid = drm_get_edid(connector, &mtk_dp->aux.ddc);- if (!enabled)
drm_bridge_chain_post_disable(bridge);Are you sure we can't get a mode set while get_edid is called?
If we can, then you could end up disabling the device while it's being powered on.
I'm a bit unsure, I need to spend more time in the drm stack to make sure. I'll get back to you when I have a definitive answer.
So, it looks like it's ok.
get_edid is your implementation of get_modes, which is called by drm_helper_probe_single_connector_modes
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_probe_hel...
This is the standard implemantion of fill_modes, which is called whenever the get_connector ioctl is called (or similar paths, like drm_client_modeset_probe)
drm_helper_probe_single_connector_modes is under the assumption that the mode_config.mutex is held though, and that the big lock. So it should be serialized there.
Just for future proofing though, it would be better to use refcounting there. Would runtime_pm work for you there?
Thx for looking into this for me. Not sure runtime_pm works here as it would only refcount if compiled with CONFIG_PM?
It should be enabled in most configurations these days, and you can always depend on it in your Kconfig option.
I'd rather use the enabled field as a refcounter instead of a boolean.
It's a bit more ad-hoc, but that would work too. Make sure to use a lock or atomic operations though
Maxime