[PATCH v2 3/3] drm/msm/dpu: switch dpu_encoder to use drm_debugfs_add_file()

[Abhinav Kumar]

On 5/23/2023 4:53 PM, Dmitry Baryshkov wrote:
> On Wed, 24 May 2023 at 02:37, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>>
>>
>>
>> On 5/21/2023 12:22 PM, Dmitry Baryshkov wrote:
>>> Use drm_debugfs_add_file() for encoder's status file. This changes the
>>> name of the status file from encoder%d/status to just encoder%d.
>>>
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>>
>> This patch depends on
>> https://patchwork.freedesktop.org/patch/538294/?series=118079&rev=1 right?
> 
> No, there is no dependency. I have sent that patch as we discussed it
> earlier. But this one is a reimplementation of the previous idea.
> 

In this patch you are also removing the early_unregister callback.

.early_unregister = dpu_encoder_early_unregister

Which we discussed was needed to balance the corner case we discussed. 
The DRM core patch fixes the corner case by calling debugfs_cleanup() 
even when drm_modeset_register_all() fails.

So isnt there a dependency?

>>
>> What is wrong with having a per encoder directory and reading from
>> there? It gives room for expanding this to dump more encoder specific
>> information.
>>
>> At the moment it looks light because we have only status but better to
>> have a directory per encoder right?
> 
> I started writing that I can not imagine additional per-encoder data,
> but then I found the generic enough piece: bridge chain enumeration.
> I'll give it additional thought and maybe I'll refactor this patch
> further.
> 

Ack,
>>
>>> ---
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 40 ++++++---------------
>>>    1 file changed, 11 insertions(+), 29 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> index af34932729db..0ac68f44ec74 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> @@ -14,6 +14,7 @@
>>>
>>>    #include <drm/drm_atomic.h>
>>>    #include <drm/drm_crtc.h>
>>> +#include <drm/drm_debugfs.h>
>>>    #include <drm/drm_file.h>
>>>    #include <drm/drm_probe_helper.h>
>>>
>>> @@ -142,7 +143,6 @@ enum dpu_enc_rc_states {
>>>     * @crtc_kickoff_cb:                Callback into CRTC that will flush & start
>>>     *                          all CTL paths
>>>     * @crtc_kickoff_cb_data:   Opaque user data given to crtc_kickoff_cb
>>> - * @debugfs_root:            Debug file system root file node
>>>     * @enc_lock:                       Lock around physical encoder
>>>     *                          create/destroy/enable/disable
>>>     * @frame_busy_mask:                Bitmask tracking which phys_enc we are still
>>> @@ -186,7 +186,6 @@ struct dpu_encoder_virt {
>>>        struct drm_crtc *crtc;
>>>        struct drm_connector *connector;
>>>
>>> -     struct dentry *debugfs_root;
>>>        struct mutex enc_lock;
>>>        DECLARE_BITMAP(frame_busy_mask, MAX_PHYS_ENCODERS_PER_VIRTUAL);
>>>        void (*crtc_frame_event_cb)(void *, u32 event);
>>> @@ -2091,7 +2090,8 @@ void dpu_encoder_helper_phys_cleanup(struct dpu_encoder_phys *phys_enc)
>>>    #ifdef CONFIG_DEBUG_FS
>>>    static int _dpu_encoder_status_show(struct seq_file *s, void *data)
>>>    {
>>> -     struct dpu_encoder_virt *dpu_enc = s->private;
>>> +     struct drm_debugfs_entry *entry = s->private;
>>> +     struct dpu_encoder_virt *dpu_enc = entry->file.data;
>>>        int i;
>>>
>>>        mutex_lock(&dpu_enc->enc_lock);
>>> @@ -2110,48 +2110,31 @@ static int _dpu_encoder_status_show(struct seq_file *s, void *data)
>>>        return 0;
>>>    }
>>>
>>> -DEFINE_SHOW_ATTRIBUTE(_dpu_encoder_status);
>>> -
>>> -static int _dpu_encoder_init_debugfs(struct drm_encoder *drm_enc)
>>> +static void _dpu_encoder_init_debugfs(struct drm_encoder *drm_enc)
>>>    {
>>>        struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
>>> -
>>> -     char name[12];
>>> +     char *name;
>>>
>>>        if (!drm_enc->dev) {
>>>                DPU_ERROR("invalid encoder or kms\n");
>>> -             return -EINVAL;
>>> +             return;
>>>        }
>>>
>>> -     snprintf(name, sizeof(name), "encoder%u", drm_enc->base.id);
>>> +     name = devm_kasprintf(drm_enc->dev->dev, GFP_KERNEL, "encoder%u", drm_enc->base.id);
>>>
>>> -     /* create overall sub-directory for the encoder */
>>> -     dpu_enc->debugfs_root = debugfs_create_dir(name,
>>> -                     drm_enc->dev->primary->debugfs_root);
>>> -
>>> -     /* don't error check these */
>>> -     debugfs_create_file("status", 0600,
>>> -             dpu_enc->debugfs_root, dpu_enc, &_dpu_encoder_status_fops);
>>> -
>>> -     return 0;
>>> +     drm_debugfs_add_file(drm_enc->dev, name, _dpu_encoder_status_show, dpu_enc);
>>>    }
>>>    #else
>>> -static int _dpu_encoder_init_debugfs(struct drm_encoder *drm_enc)
>>> +static void _dpu_encoder_init_debugfs(struct drm_encoder *drm_enc)
>>>    {
>>> -     return 0;
>>>    }
>>>    #endif
>>>
>>>    static int dpu_encoder_late_register(struct drm_encoder *encoder)
>>>    {
>>> -     return _dpu_encoder_init_debugfs(encoder);
>>> -}
>>> -
>>> -static void dpu_encoder_early_unregister(struct drm_encoder *encoder)
>>> -{
>>> -     struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(encoder);
>>> +     _dpu_encoder_init_debugfs(encoder);
>>>
>>> -     debugfs_remove_recursive(dpu_enc->debugfs_root);
>>> +     return 0;
>>>    }
>>>
>>>    static int dpu_encoder_virt_add_phys_encs(
>>> @@ -2380,7 +2363,6 @@ static const struct drm_encoder_helper_funcs dpu_encoder_helper_funcs = {
>>>    static const struct drm_encoder_funcs dpu_encoder_funcs = {
>>>                .destroy = dpu_encoder_destroy,
>>>                .late_register = dpu_encoder_late_register,
>>> -             .early_unregister = dpu_encoder_early_unregister,
>>>    };
>>>
>>>    int dpu_encoder_setup(struct drm_device *dev, struct drm_encoder *enc,
> 
> 
>