[PATCH 7/8] drm/i915/dsc: Add debugfs entry to validate DSC fractional bpp
Jani Nikula
jani.nikula at intel.com
Fri Sep 22 12:28:24 UTC 2023
On Thu, 21 Sep 2023, "Sharma, Swati2" <swati2.sharma at intel.com> wrote:
> On 21-Sep-23 5:44 PM, Jani Nikula wrote:
>> On Thu, 21 Sep 2023, "Sharma, Swati2" <swati2.sharma at intel.com> wrote:
>>> On 21-Sep-23 1:30 PM, Jani Nikula wrote:
>>>> On Wed, 13 Sep 2023, Mitul Golani <mitulkumar.ajitkumar.golani at intel.com> wrote:
>>>>> From: Swati Sharma <swati2.sharma at intel.com>
>>>>>
>>>>> 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 at intel.com>
>>>>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>>>>> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>
>>>>> Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>
>>>>> ---
>>>>> .../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?
>>>
>>> Hi Jani,
>>> Followed same strategy as we are doing for other dsc scenarios like
>>> force_dsc.
>>> Even naming convention followed same as other dsc stuff like
>>> Force_DSC_Enable, etc.
>>> All DSC related enteries have underscores in its naming convention.
>>
>> There's value in that, though maybe my comment highlights I'm not fond
>> of the existing stuff. ;)
>
> Sure, I can work on cleanup part later.
>
>>
>>> May be i can consolidate other dsc debugfs enteries into
>>> one as a cleanup task later. But it will impact IGT aswell. And i'm not
>>> sure if we can break compatibility but since IGT (intel as only vendor)
>>> is the only consumer, may be we change at both places and clean it up.
>>
>> We can do what we want with debugfs, as long as we change both the
>> driver and igt.
>
> Sure, will make corresponding changes in both IGT and KMD.
>
>>
>>>
>>>>
>>>>> +
>>>>> +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;
>>>
>>> Done.
>>>
>>>>
>>>>> + 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.
>>>
>>> Done.
>>>
>>>>
>>>>> +
>>>>> + drm_dbg(&i915->drm,
>>>>> + "Copied %zu bytes from user to force fractional bpp for DSC\n", len);
>>>>
>>>> That's useless.
>>>
>>> Done.
>>>
>>>>
>>>>> +
>>>>> + 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?
>>>
>>> Yes, to know when fractional bpp is enabled.
>>
>> I think it would be more useful to debug log this at the use site, not
>> when you're setting the debugfs knob.
>
> We already have those in IGT. Like said, to maintain consitency with
> other dsc func() like fec_support_write(), this debug print is added
> here. I can drop and will drop from fec_support_write() too during cleanup.
>
>>
>> BR,
>> Jani.
>>
>>
>>
>>
>>>
>>>>
>>>>> + 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;
>>>>
>>
>
> With above KMD changes IGT is already rb'ed and validated
> https://patchwork.freedesktop.org/series/117493/#rev12
> I request if we can get ack on this. As cleanup task,
> will make changes as requested.
Okay then.
BR,
Jani.
--
Jani Nikula, Intel
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