[PATCH] drm/amd/display: Expose connector VRR range via debugfs

[Koenig, Christian]

Am 24.01.19 um 18:56 schrieb Wentland, Harry:
>
> On 2019-01-24 12:41 p.m., Christian König wrote:
>> Am 24.01.19 um 18:06 schrieb Nicholas Kazlauskas:
>>> [Why]
>>> It's useful to know the min and max vrr range for IGT testing.
>>>
>>> [How]
>>> Expose the min and max vfreq for the connector via a debugfs file
>>> on the connector, "vrr_range".
>>>
>>> Example usage: cat /sys/kernel/debug/dri/0/DP-1/vrr_range
>>>
>>> Cc: Harry Wentland <harry.wentland at amd.com>
>>> Cc: Leo Li <sunpeng.li at amd.com>
>>> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
>> Oh, nice that is indeed useful. Acked-by: Christian König <christian.koenig at amd.com>
>>
> FYI, IGT test case making use of this: https://patchwork.freedesktop.org/patch/275982/

BTW: I have a flaky 4k VRR monitor here which at around 50% of all boots 
is not correctly detected on a Vega10.

It used to work fine about a month ago and same cable/etc work fine on a 
Tonga, so most likely a regression.

Not my highest priority at the moment, but are you guys already working 
on this? If not I will try to start to bisect when I have time.

Christian.

>
> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
>
> Harry
>
>>> ---
>>>    .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 22 ++++++++++++++++++-
>>>    1 file changed, 21 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>>> index cca3e16cda4f..4a55cde027cf 100644
>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>>> @@ -671,6 +671,25 @@ static ssize_t dp_phy_test_pattern_debugfs_write(struct file *f, const char __us
>>>        return bytes_from_user;
>>>    }
>>>    +/*
>>> + * Returns the min and max vrr vfreq through the connector's debugfs file.
>>> + * Example usage: cat /sys/kernel/debug/dri/0/DP-1/vrr_range
>>> + */
>>> +static int vrr_range_show(struct seq_file *m, void *data)
>>> +{
>>> +    struct drm_connector *connector = m->private;
>>> +    struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
>>> +
>>> +    if (connector->status != connector_status_connected)
>>> +        return -ENODEV;
>>> +
>>> +    seq_printf(m, "Min: %u\n", (unsigned int)aconnector->min_vfreq);
>>> +    seq_printf(m, "Max: %u\n", (unsigned int)aconnector->max_vfreq);
>>> +
>>> +    return 0;
>>> +}
>>> +DEFINE_SHOW_ATTRIBUTE(vrr_range);
>>> +
>>>    static const struct file_operations dp_link_settings_debugfs_fops = {
>>>        .owner = THIS_MODULE,
>>>        .read = dp_link_settings_read,
>>> @@ -697,7 +716,8 @@ static const struct {
>>>    } dp_debugfs_entries[] = {
>>>            {"link_settings", &dp_link_settings_debugfs_fops},
>>>            {"phy_settings", &dp_phy_settings_debugfs_fop},
>>> -        {"test_pattern", &dp_phy_test_pattern_fops}
>>> +        {"test_pattern", &dp_phy_test_pattern_fops},
>>> +        {"vrr_range", &vrr_range_fops}
>>>    };
>>>      int connector_debugfs_init(struct amdgpu_dm_connector *connector)