On Mon, Jan 08, 2024 at 02:07:23PM +0200, Stanislav Lisovskiy wrote:
> For validation purposes, it might be useful to be able to
> force Bigjoiner mode, even if current dotclock/resolution
> do not require that.
> Lets add such to option to debugfs.
>
> v2: - Apparently intel_dp_need_bigjoiner can't be used, when
> debugfs entry is created so lets just check manually
> the DISPLAY_VER.
>
> v3: - Switch to intel_connector from drm_connector(Jani Nikula)
> - Remove redundant modeset lock(Jani Nikula)
> - Use kstrtobool_from_user for boolean value(Jani Nikula)
>
> v4: - Apply the changes to proper function(Jani Nikula)
>
> v5: - Removed unnecessary check from i915_bigjoiner_enable_show
> (Ville Syrjälä)
> - Added eDP connector check to intel_connector_debugfs_add
> (Ville Syrjälä)
> - Removed debug message in order to prevent dmesg flooding
> (Ville Syrjälä)
>
> v6: - Assume now always that m->private is intel_connector
> - Fixed other similar conflicts
>
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
> ---
> .../drm/i915/display/intel_display_debugfs.c | 59 +++++++++++++++++++
> .../drm/i915/display/intel_display_types.h | 2 +
> drivers/gpu/drm/i915/display/intel_dp.c | 3 +-
> 3 files changed, 63 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index d951edb366871..353e71b4e1db2 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -1413,6 +1413,22 @@ out: drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
> return ret;
> }
>
> +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> +{
> + struct intel_connector *connector = m->private;
> + struct intel_encoder *encoder = intel_attached_encoder(connector);
> + struct intel_dp *intel_dp;
> +
> + if (!encoder)
> + return -ENODEV;
> +
> + intel_dp = enc_to_intel_dp(encoder);
> +
> + seq_printf(m, "Bigjoiner enable: %d\n", intel_dp->force_bigjoiner_enable);
So it's a per-connector debugfs knob but we track it in the
SST DP encoder? That's rather odd, and not going to work for MST.
> +
> + return 0;
> +}
> +
> static ssize_t i915_dsc_output_format_write(struct file *file,
> const char __user *ubuf,
> size_t len, loff_t *offp)
> @@ -1434,12 +1450,39 @@ static ssize_t i915_dsc_output_format_write(struct file *file,
> return len;
> }
>
> +static ssize_t i915_bigjoiner_enable_fops_write(struct file *file,
> + const char __user *ubuf,
> + size_t len, loff_t *offp)
> +{
> + struct seq_file *m = file->private_data;
> + struct intel_connector *connector = m->private;
> + struct intel_encoder *encoder = intel_attached_encoder(connector);
> + struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> + bool bigjoiner_en = 0;
> + int ret;
> +
> + ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> + if (ret < 0)
> + return ret;
> +
> + intel_dp->force_bigjoiner_enable = bigjoiner_en;
> + *offp += len;
> +
> + return len;
> +}
> +
> static int i915_dsc_output_format_open(struct inode *inode,
> struct file *file)
> {
> return single_open(file, i915_dsc_output_format_show, inode->i_private);
> }
>
> +static int i915_bigjoiner_enable_open(struct inode *inode,
> + struct file *file)
> +{
> + return single_open(file, i915_bigjoiner_enable_show, inode->i_private);
> +}
> +
> static const struct file_operations i915_dsc_output_format_fops = {
> .owner = THIS_MODULE,
> .open = i915_dsc_output_format_open,
> @@ -1527,6 +1570,15 @@ static const struct file_operations i915_dsc_fractional_bpp_fops = {
> .write = i915_dsc_fractional_bpp_write
> };
>
> +static const struct file_operations i915_bigjoiner_enable_fops = {
> + .owner = THIS_MODULE,
> + .open = i915_bigjoiner_enable_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> + .write = i915_bigjoiner_enable_fops_write
> +};
Why are we implementing this long-hand for a simple boolean flag?
> +
> /*
> * Returns the Current CRTC's bpc.
> * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> @@ -1608,6 +1660,13 @@ void intel_connector_debugfs_add(struct intel_connector *connector)
> connector, &i915_dsc_fractional_bpp_fops);
> }
>
> + if (DISPLAY_VER(i915) >= 11 &&
> + (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> + connector_type == DRM_MODE_CONNECTOR_eDP)) {
> + debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> + &connector->base, &i915_bigjoiner_enable_fops);
> + }
> +
> if (connector_type == DRM_MODE_CONNECTOR_DSI ||
> connector_type == DRM_MODE_CONNECTOR_eDP ||
> connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index b9b9d9f2bc0ba..e4c5a44dd02f5 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1768,6 +1768,8 @@ struct intel_dp {
> bool is_mst;
> int active_mst_links;
>
> + bool force_bigjoiner_enable;
> +
> /* connector directly attached - won't be use for modeset in mst world */
> struct intel_connector *attached_connector;
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 9ff0cbd9c0df5..525ab926582d5 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1208,7 +1208,8 @@ bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
> if (!intel_dp_can_bigjoiner(intel_dp))
> return false;
>
> - return clock > i915->max_dotclk_freq || hdisplay > 5120;
> + return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> + intel_dp->force_bigjoiner_enable;
> }
>
> static enum drm_mode_status
> --
> 2.37.3
--
Ville Syrjälä
Intel
