On Thu, Nov 15, 2018 at 05:39:42PM -0800, Manasi Navare wrote:
> On Tue, Nov 13, 2018 at 05:52:28PM -0800, Manasi Navare wrote:
> > DSC can be supported per DP connector. This patch adds a per connector
> > debugfs node to expose DSC support capability by the kernel.
> > The same node can be used from userspace to force DSC enable.
> >
> > force_dsc_en written through this debugfs node is used to force
> > DSC even for lower resolutions.
> >
> > v4:
> > * Add missed connector_status check (Manasi)
> > * Create i915_dsc_support node only for Gen >=10 (manasi)
> > * Access intel_dp->dsc_dpcd only if its not NULL (Manasi)
> > v3:
> > * Combine Force_dsc_en with this patch (Ville)
> > v2:
> > * Use kstrtobool_from_user to avoid explicit error checking (Lyude)
> > * Rebase on drm-tip (Manasi)
> >
> > Cc: Rodrigo Vivi <rodrigo.v...@intel.com>
> > Cc: Ville Syrjala <ville.syrj...@linux.intel.com>
> > Cc: Anusha Srivatsa <anusha.sriva...@intel.com>
> > Cc: Lyude Paul <ly...@redhat.com>
> > Signed-off-by: Manasi Navare <manasi.d.nav...@intel.com>
> > Reviewed-by: Lyude Paul <ly...@redhat.com>
> > ---
> > drivers/gpu/drm/i915/i915_debugfs.c | 77 +++++++++++++++++++++++++++++
> > drivers/gpu/drm/i915/intel_dp.c | 3 +-
> > drivers/gpu/drm/i915/intel_drv.h | 3 ++
> > 3 files changed, 82 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c
> > b/drivers/gpu/drm/i915/i915_debugfs.c
> > index 670db5073d70..3c112bb225d6 100644
> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > @@ -5074,6 +5074,76 @@ static int i915_hdcp_sink_capability_show(struct
> > seq_file *m, void *data)
> > }
> > DEFINE_SHOW_ATTRIBUTE(i915_hdcp_sink_capability);
> >
> > +static int i915_dsc_support_show(struct seq_file *m, void *data)
> > +{
> > + struct drm_connector *connector = m->private;
> > + struct intel_encoder *encoder = intel_attached_encoder(connector);
> > + struct intel_dp *intel_dp =
> > + enc_to_intel_dp(&encoder->base);
> > + struct intel_crtc *crtc;
> > + struct intel_crtc_state *crtc_state;
> > +
> > + if (connector->status != connector_status_connected)
> > + return -ENODEV;
> > +
> > + crtc = to_intel_crtc(encoder->base.crtc);
> > + crtc_state = to_intel_crtc_state(crtc->base.state);
This stuff is broken. If you want to root around in the atomic states
you need to grab some locks first.
> > + drm_modeset_lock(&crtc->base.mutex, NULL);
> > + seq_printf(m, "Enabled: %s\n",
> > + yesno(crtc_state->dsc_params.compression_enable));
> > + if (intel_dp->dsc_dpcd)
> > + seq_printf(m, "Supported: %s\n",
> > + yesno(drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)));
>
> I think this supported should also use the intel_dp_supports_dsc() helper so
> it checks for sink support and platform support as well.
>
> Ville, what do you think?
Possibly. We may want to report per-crtc whether DSC is possible or not
(due to transcoder A not being capable of DSC). And to do that we
actually need to change intel_dp_source_supports_dsc() & co. to not take
the crtc state, and rather we just need to pass in the transcoder. That
would mean we have to determine the correct transcoder here. Perhaps
a better alternative would be to pass in pipe/crtc + port and let the
function derive the transcoder itself. That would keep the
pipe+port->transcoder logic in one place. Actually we have that logic
in two places at least already (intel_ddi_compute_config() and
intel_ddi_connector_get_hw_state()). We could extract that bit into
a small helper that gets called by all three places.
>
> Manasi
>
> > + drm_modeset_unlock(&crtc->base.mutex);
> > +
> > + return 0;
> > +}
> > +
> > +static ssize_t i915_dsc_support_write(struct file *file,
> > + const char __user *ubuf,
> > + size_t len, loff_t *offp)
> > +{
> > + bool dsc_enable = false;
> > + int ret;
> > + struct drm_connector *connector =
> > + ((struct seq_file *)file->private_data)->private;
> > + struct intel_encoder *encoder = intel_attached_encoder(connector);
> > + struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> > +
> > + if (len == 0)
> > + return 0;
> > +
> > + DRM_DEBUG_DRIVER("Copied %d bytes from user to force DSC\n",
> > + (unsigned int)len);
> > +
> > + ret = kstrtobool_from_user(ubuf, len, &dsc_enable);
> > + if (ret < 0)
> > + return ret;
> > +
> > + DRM_DEBUG_DRIVER("Got %s for DSC Enable\n",
> > + (dsc_enable) ? "true" : "false");
> > + intel_dp->force_dsc_en = dsc_enable;
> > +
> > + *offp += len;
> > + return len;
> > +}
> > +
> > +static int i915_dsc_support_open(struct inode *inode,
> > + struct file *file)
> > +{
> > + return single_open(file, i915_dsc_support_show,
> > + inode->i_private);
> > +}
> > +
> > +static const struct file_operations i915_dsc_support_fops = {
> > + .owner = THIS_MODULE,
> > + .open = i915_dsc_support_open,
> > + .read = seq_read,
> > + .llseek = seq_lseek,
> > + .release = single_release,
> > + .write = i915_dsc_support_write
> > +};
> > +
> > /**
> > * i915_debugfs_connector_add - add i915 specific connector debugfs files
> > * @connector: pointer to a registered drm_connector
> > @@ -5086,6 +5156,7 @@ DEFINE_SHOW_ATTRIBUTE(i915_hdcp_sink_capability);
> > int i915_debugfs_connector_add(struct drm_connector *connector)
> > {
> > struct dentry *root = connector->debugfs_entry;
> > + struct drm_i915_private *dev_priv = to_i915(connector->dev);
> >
> > /* The connector must have been registered beforehands. */
> > if (!root)
> > @@ -5110,5 +5181,11 @@ int i915_debugfs_connector_add(struct drm_connector
> > *connector)
> > connector, &i915_hdcp_sink_capability_fops);
> > }
> >
> > + if (INTEL_GEN(dev_priv) >= 10 &&
> > + (connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > + connector->connector_type == DRM_MODE_CONNECTOR_eDP))
> > + debugfs_create_file("i915_dsc_support", S_IRUGO, root,
> > + connector, &i915_dsc_support_fops);
> > +
> > return 0;
> > }
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > b/drivers/gpu/drm/i915/intel_dp.c
> > index b43a77bf42df..99e0dd0e32d6 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -2042,7 +2042,7 @@ intel_dp_compute_link_config(struct intel_encoder
> > *encoder,
> > &limits);
> >
> > /* enable compression if the mode doesn't fit available BW */
> > - if (!ret) {
> > + if (!ret || intel_dp->force_dsc_en) {
> > if (!intel_dp_dsc_compute_config(intel_dp, pipe_config,
> > conn_state, &limits))
> > return false;
> > @@ -2135,6 +2135,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> > if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK)
> > return false;
> >
> > + DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> > if (!intel_dp_compute_link_config(encoder, pipe_config, conn_state))
> > return false;
> >
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index 92e987fc3d9f..9eeb08142327 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1200,6 +1200,9 @@ struct intel_dp {
> >
> > /* Displayport compliance testing */
> > struct intel_dp_compliance compliance;
> > +
> > + /* Display stream compression testing */
> > + bool force_dsc_en;
> > };
> >
> > enum lspcon_vendor {
> > --
> > 2.19.1
> >
--
Ville Syrjälä
Intel
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