linux-kernel - Re: [PATCH] drm: sysfs: Add to get current mode

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Date:   Wed, 5 Aug 2020 18:03:15 +0800
From:   Huang Jiachai <hjc@...k-chips.com>
To:     Daniel Vetter <daniel@...ll.ch>
Cc:     Heiko Stübner <heiko@...ech.de>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Tao Huang <huangtao@...k-chips.com>,
        Andy Yan <andy.yan@...k-chips.com>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Kever Yang <kever.yang@...k-chips.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm: sysfs: Add to get current mode

Hi Daniel

在 2020/8/5 17:36, Daniel Vetter 写道:
> On Wed, Aug 5, 2020 at 10:37 AM Sandy Huang <hjc@...k-chips.com> wrote:
>> add this node to get the current true mode.
>>
>> Signed-off-by: Sandy Huang <hjc@...k-chips.com>
> Uh what's this for? Since it's sysfs, I guess there's something
> parsing this, which means we'd kinda need to have that piece too.
>
> If it's just for debugging purposes, then we already have this
> information in debugfs, together with everything else that's in the
> atomic modeset state.
> -Daniel

yes, this is just for debug;

and i get the information what i need from cat 
/sys/kernel/debug/dri/0/state, thanks.

>> ---
>>   drivers/gpu/drm/drm_sysfs.c | 30 ++++++++++++++++++++++++++++++
>>   1 file changed, 30 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
>> index 939f0032aab1..f39bcd34853b 100644
>> --- a/drivers/gpu/drm/drm_sysfs.c
>> +++ b/drivers/gpu/drm/drm_sysfs.c
>> @@ -19,6 +19,7 @@
>>   #include <linux/slab.h>
>>
>>   #include <drm/drm_connector.h>
>> +#include <drm/drm_crtc.h>
>>   #include <drm/drm_device.h>
>>   #include <drm/drm_file.h>
>>   #include <drm/drm_modes.h>
>> @@ -236,16 +237,45 @@ static ssize_t modes_show(struct device *device,
>>          return written;
>>   }
>>
>> +static ssize_t current_mode_show(struct device *device,
>> +                     struct device_attribute *attr,
>> +                     char *buf)
>> +{
>> +       struct drm_connector *connector = to_drm_connector(device);
>> +       struct drm_display_mode *mode;
>> +       struct drm_crtc_state *crtc_state;
>> +       bool interlaced;
>> +       int written = 0;
>> +
>> +       if (!connector->state || !connector->state->crtc)
>> +               return written;
>> +
>> +       crtc_state = connector->state->crtc->state;
>> +       if (!crtc_state)
>> +               return written;
>> +
>> +       mode = &crtc_state->mode;
>> +
>> +       interlaced = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
>> +       written += snprintf(buf + written, PAGE_SIZE - written, "%dx%d%s%d\n",
>> +                           mode->hdisplay, mode->vdisplay,
>> +                           interlaced ? "i" : "p", drm_mode_vrefresh(mode));
>> +
>> +       return written;
>> +}
>> +
>>   static DEVICE_ATTR_RW(status);
>>   static DEVICE_ATTR_RO(enabled);
>>   static DEVICE_ATTR_RO(dpms);
>>   static DEVICE_ATTR_RO(modes);
>> +static DEVICE_ATTR_RO(current_mode);
>>
>>   static struct attribute *connector_dev_attrs[] = {
>>          &dev_attr_status.attr,
>>          &dev_attr_enabled.attr,
>>          &dev_attr_dpms.attr,
>>          &dev_attr_modes.attr,
>> +       &dev_attr_current_mode.attr,
>>          NULL
>>   };
>>
>> --
>> 2.17.1
>>
>>
>>
>
-- 
Best Regard

黄家钗
Sandy Huang
Addr: 福州市鼓楼区铜盘路软件大道89号福州软件园A区21号楼(350003)
       No. 21 Building, A District, No.89,software Boulevard Fuzhou,Fujian,PRC
Tel：+86 0591-87884919  8690
E-mail：hjc@...k-chips.com