On Wed, 13 Sep 2023, Mitul Golani <mitulkumar.ajitkumar.golani@xxxxxxxxx> wrote:
> From: Swati Sharma <swati2.sharma@xxxxxxxxx>
>
> DSC_Sink_BPP_Precision entry is added to i915_dsc_fec_support_show
> to depict sink's precision.
> Also, new debugfs entry is created to enforce fractional bpp.
> If Force_DSC_Fractional_BPP_en is set then while iterating over
> output bpp with fractional step size we will continue if output_bpp is
> computed as integer. With this approach, we will be able to validate
> DSC with fractional bpp.
>
> v2:
> Add drm_modeset_unlock to new line(Suraj)
>
> Signed-off-by: Swati Sharma <swati2.sharma@xxxxxxxxx>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@xxxxxxxxx>
> Reviewed-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> ---
> .../drm/i915/display/intel_display_debugfs.c | 83 +++++++++++++++++++
> .../drm/i915/display/intel_display_types.h | 1 +
> 2 files changed, 84 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index f05b52381a83..776ab96def1f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -1244,6 +1244,8 @@ static int i915_dsc_fec_support_show(struct seq_file *m, void *data)
> DP_DSC_YCbCr420_Native)),
> str_yes_no(drm_dp_dsc_sink_supports_format(intel_dp->dsc_dpcd,
> DP_DSC_YCbCr444)));
> + seq_printf(m, "DSC_Sink_BPP_Precision: %d\n",
> + drm_dp_dsc_sink_bpp_incr(intel_dp->dsc_dpcd));
> seq_printf(m, "Force_DSC_Enable: %s\n",
> str_yes_no(intel_dp->force_dsc_en));
> if (!intel_dp_is_edp(intel_dp))
> @@ -1436,6 +1438,84 @@ static const struct file_operations i915_dsc_output_format_fops = {
> .write = i915_dsc_output_format_write
> };
>
> +static int i915_dsc_fractional_bpp_show(struct seq_file *m, void *data)
> +{
> + struct drm_connector *connector = m->private;
> + struct drm_device *dev = connector->dev;
> + struct drm_crtc *crtc;
> + struct intel_dp *intel_dp;
> + struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
> + int ret;
> +
> + if (!encoder)
> + return -ENODEV;
> +
> + ret = drm_modeset_lock_single_interruptible(&dev->mode_config.connection_mutex);
> + if (ret)
> + return ret;
> +
> + crtc = connector->state->crtc;
> + if (connector->status != connector_status_connected || !crtc) {
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + intel_dp = intel_attached_dp(to_intel_connector(connector));
> + seq_printf(m, "Force_DSC_Fractional_BPP_Enable: %s\n",
> + str_yes_no(intel_dp->force_dsc_fractional_bpp_en));
Why "Force_DSC_Fractional_BPP_Enable" in the output?
Usually debugfs files, like sysfs files, for stuff like this should be
attributes, one thing per file. Why print a long name for it, if the
name of the debugfs file is the name of the attribute?
And even if you print it for humans, why the underscores?
> +
> +out:
> + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +
> + return ret;
> +}
> +
> +static ssize_t i915_dsc_fractional_bpp_write(struct file *file,
> + const char __user *ubuf,
> + size_t len, loff_t *offp)
> +{
> + struct drm_connector *connector =
> + ((struct seq_file *)file->private_data)->private;
I know this is copy-pasted from elsewhere, but really it's nicer to
avoid the cast, and copy-paste from the places that get this right:
struct seq_file *m = file->private_data;
struct drm_connector *connector = m->private;
> + struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
> + struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> + struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> + bool dsc_fractional_bpp_enable = false;
> + int ret;
> +
> + if (len == 0)
> + return 0;
kstrtobool_from_user() has this covered.
> +
> + drm_dbg(&i915->drm,
> + "Copied %zu bytes from user to force fractional bpp for DSC\n", len);
That's useless.
> +
> + ret = kstrtobool_from_user(ubuf, len, &dsc_fractional_bpp_enable);
> + if (ret < 0)
> + return ret;
> +
> + drm_dbg(&i915->drm, "Got %s for DSC Fractional BPP Enable\n",
> + (dsc_fractional_bpp_enable) ? "true" : "false");
Is this useful?
> + intel_dp->force_dsc_fractional_bpp_en = dsc_fractional_bpp_enable;
> +
> + *offp += len;
> +
> + return len;
> +}
> +
> +static int i915_dsc_fractional_bpp_open(struct inode *inode,
> + struct file *file)
> +{
> + return single_open(file, i915_dsc_fractional_bpp_show, inode->i_private);
> +}
> +
> +static const struct file_operations i915_dsc_fractional_bpp_fops = {
> + .owner = THIS_MODULE,
> + .open = i915_dsc_fractional_bpp_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> + .write = i915_dsc_fractional_bpp_write
> +};
> +
> /*
> * Returns the Current CRTC's bpc.
> * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> @@ -1513,6 +1593,9 @@ void intel_connector_debugfs_add(struct intel_connector *intel_connector)
>
> debugfs_create_file("i915_dsc_output_format", 0644, root,
> connector, &i915_dsc_output_format_fops);
> +
> + debugfs_create_file("i915_dsc_fractional_bpp", 0644, root,
> + connector, &i915_dsc_fractional_bpp_fops);
> }
>
> if (connector->connector_type == DRM_MODE_CONNECTOR_DSI ||
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 69bcabec4a29..27b31cb4c7b4 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1797,6 +1797,7 @@ struct intel_dp {
> /* Display stream compression testing */
> bool force_dsc_en;
> int force_dsc_output_format;
> + bool force_dsc_fractional_bpp_en;
> int force_dsc_bpc;
>
> bool hobl_failed;
--
Jani Nikula, Intel
