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Subject: Re: [PATCH v6 24/30] drm/rockchip: Disable PSR on input events
To:     Andrzej Hajda <a.hajda@samsung.com>, architt@codeaurora.org,
        inki.dae@samsung.com, thierry.reding@gmail.com, hjc@rock-chips.com,
        seanpaul@chromium.org, airlied@linux.ie, tfiga@chromium.org,
        heiko@sntech.de
Cc:     dri-devel@lists.freedesktop.org, dianders@chromium.org,
        ykk@rock-chips.com, kernel@collabora.com, m.szyprowski@samsung.com,
        linux-samsung-soc@vger.kernel.org, jy0922.shim@samsung.com,
        rydberg@bitmath.org, krzk@kernel.org,
        linux-rockchip@lists.infradead.org, kgene@kernel.org,
        linux-input@vger.kernel.org, orjan.eide@arm.com,
        wxt@rock-chips.com, jeffy.chen@rock-chips.com,
        linux-arm-kernel@lists.infradead.org, mark.yao@rock-chips.com,
        wzz@rock-chips.com, hl@rock-chips.com, jingoohan1@gmail.com,
        sw0312.kim@samsung.com, linux-kernel@vger.kernel.org,
        kyungmin.park@samsung.com, Laurent.pinchart@ideasonboard.com,
        kuankuan.y@gmail.com, hshi@chromium.org,
        "Kristian H. Kristensen" <hoegsberg@google.com>
References: <20180405095000.9756-1-enric.balletbo@collabora.com>
 <CGME20180405095330epcas1p33487d73838f08a65ce7935f0d3e8b9e4@epcas1p3.samsung.com>
 <20180405095000.9756-25-enric.balletbo@collabora.com>
 <9de97922-da64-d914-8b8c-ed064056edbd@samsung.com>
From:   Enric Balletbo i Serra <enric.balletbo@collabora.com>
Message-ID: <8f267fc9-094e-6fee-9978-7dfc95b01e01@collabora.com>
Date:   Fri, 20 Apr 2018 15:51:51 +0200
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Hi Andrzej,

On 20/04/18 15:47, Andrzej Hajda wrote:
> Hi Enric,
> 
> 
> On 05.04.2018 11:49, Enric Balletbo i Serra wrote:
>> From: "Kristian H. Kristensen" <hoegsberg@google.com>
>>
>> To improve PSR exit latency, we speculatively start exiting when we
>> receive input events. Occasionally, this may lead to false positives,
>> but most of the time we get a head start on coming out of PSR. Depending
>> on how userspace takes to produce a new frame in response to the event,
>> this can completely hide the exit latency. In case of Chrome OS, we
>> typically get the input notifier 50ms or more before the dirty_fb
>> triggered exit.
> 
> This patch is quite controversial and require more attention/discussion
> and probably changes.

Agree.

> The rest of the patches is OK, and all have r-b/t-b tags.
> If you prefer I can merge all other patches, if you rebase patches 25-30
> on top of patch 23, or I can only merge patches 01-23.
> What do you prefer?
> 

If the patches 25-30 are also fine let me rebase those, and lets start a
discussion regarding patches 23-25 on another patchset. I'll send another
version without 23-25.

Regards,
 Enric

> Regards
> Andrzej
> 
>>
>> Signed-off-by: Kristian H. Kristensen <hoegsberg@google.com>
>> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>
>>  drivers/gpu/drm/rockchip/rockchip_drm_psr.c | 134 ++++++++++++++++++++++++++++
>>  1 file changed, 134 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
>> index 9376f4396b6b..a107845ba97c 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
>> @@ -12,6 +12,8 @@
>>   * GNU General Public License for more details.
>>   */
>>  
>> +#include <linux/input.h>
>> +
>>  #include <drm/drmP.h>
>>  #include <drm/drm_crtc_helper.h>
>>  
>> @@ -35,6 +37,9 @@ struct psr_drv {
>>  	enum psr_state		state;
>>  
>>  	struct delayed_work	flush_work;
>> +	struct work_struct	disable_work;
>> +
>> +	struct input_handler    input_handler;
>>  
>>  	int (*set)(struct drm_encoder *encoder, bool enable);
>>  };
>> @@ -133,6 +138,18 @@ static void psr_flush_handler(struct work_struct *work)
>>  	mutex_unlock(&psr->lock);
>>  }
>>  
>> +static void psr_disable_handler(struct work_struct *work)
>> +{
>> +	struct psr_drv *psr = container_of(work, struct psr_drv, disable_work);
>> +
>> +	/* If the state has changed since we initiated the flush, do nothing */
>> +	mutex_lock(&psr->lock);
>> +	if (psr->state == PSR_ENABLE)
>> +		psr_set_state_locked(psr, PSR_FLUSH);
>> +	mutex_unlock(&psr->lock);
>> +	mod_delayed_work(system_wq, &psr->flush_work, PSR_FLUSH_TIMEOUT_MS);
>> +}
>> +
>>  /**
>>   * rockchip_drm_psr_activate - activate PSR on the given pipe
>>   * @encoder: encoder to obtain the PSR encoder
>> @@ -173,6 +190,7 @@ int rockchip_drm_psr_deactivate(struct drm_encoder *encoder)
>>  	psr->active = false;
>>  	mutex_unlock(&psr->lock);
>>  	cancel_delayed_work_sync(&psr->flush_work);
>> +	cancel_work_sync(&psr->disable_work);
>>  
>>  	return 0;
>>  }
>> @@ -226,6 +244,95 @@ void rockchip_drm_psr_flush_all(struct drm_device *dev)
>>  }
>>  EXPORT_SYMBOL(rockchip_drm_psr_flush_all);
>>  
>> +static void psr_input_event(struct input_handle *handle,
>> +			    unsigned int type, unsigned int code,
>> +			    int value)
>> +{
>> +	struct psr_drv *psr = handle->handler->private;
>> +
>> +	schedule_work(&psr->disable_work);
>> +}
>> +
>> +static int psr_input_connect(struct input_handler *handler,
>> +			     struct input_dev *dev,
>> +			     const struct input_device_id *id)
>> +{
>> +	struct input_handle *handle;
>> +	int error;
>> +
>> +	handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
>> +	if (!handle)
>> +		return -ENOMEM;
>> +
>> +	handle->dev = dev;
>> +	handle->handler = handler;
>> +	handle->name = "rockchip-psr";
>> +
>> +	error = input_register_handle(handle);
>> +	if (error)
>> +		goto err2;
>> +
>> +	error = input_open_device(handle);
>> +	if (error)
>> +		goto err1;
>> +
>> +	return 0;
>> +
>> +err1:
>> +	input_unregister_handle(handle);
>> +err2:
>> +	kfree(handle);
>> +	return error;
>> +}
>> +
>> +static void psr_input_disconnect(struct input_handle *handle)
>> +{
>> +	input_close_device(handle);
>> +	input_unregister_handle(handle);
>> +	kfree(handle);
>> +}
>> +
>> +/* Same device ids as cpu-boost */
>> +static const struct input_device_id psr_ids[] = {
>> +	{
>> +		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
>> +			 INPUT_DEVICE_ID_MATCH_ABSBIT,
>> +		.evbit = { BIT_MASK(EV_ABS) },
>> +		.absbit = { [BIT_WORD(ABS_MT_POSITION_X)] =
>> +			    BIT_MASK(ABS_MT_POSITION_X) |
>> +			    BIT_MASK(ABS_MT_POSITION_Y) },
>> +	}, /* multi-touch touchscreen */
>> +	{
>> +		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
>> +		.evbit = { BIT_MASK(EV_ABS) },
>> +		.absbit = { [BIT_WORD(ABS_X)] = BIT_MASK(ABS_X) }
>> +
>> +	}, /* stylus or joystick device */
>> +	{
>> +		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
>> +		.evbit = { BIT_MASK(EV_KEY) },
>> +		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
>> +	}, /* pointer (e.g. trackpad, mouse) */
>> +	{
>> +		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
>> +		.evbit = { BIT_MASK(EV_KEY) },
>> +		.keybit = { [BIT_WORD(KEY_ESC)] = BIT_MASK(KEY_ESC) },
>> +	}, /* keyboard */
>> +	{
>> +		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
>> +				INPUT_DEVICE_ID_MATCH_KEYBIT,
>> +		.evbit = { BIT_MASK(EV_KEY) },
>> +		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
>> +	}, /* joysticks not caught by ABS_X above */
>> +	{
>> +		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
>> +				INPUT_DEVICE_ID_MATCH_KEYBIT,
>> +		.evbit = { BIT_MASK(EV_KEY) },
>> +		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
>> +	}, /* gamepad */
>> +	{ },
>> +};
>> +
>>  /**
>>   * rockchip_drm_psr_register - register encoder to psr driver
>>   * @encoder: encoder that obtain the PSR function
>> @@ -239,6 +346,7 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder,
>>  {
>>  	struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
>>  	struct psr_drv *psr;
>> +	int error;
>>  
>>  	if (!encoder || !psr_set)
>>  		return -EINVAL;
>> @@ -248,6 +356,7 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder,
>>  		return -ENOMEM;
>>  
>>  	INIT_DELAYED_WORK(&psr->flush_work, psr_flush_handler);
>> +	INIT_WORK(&psr->disable_work, psr_disable_handler);
>>  	mutex_init(&psr->lock);
>>  
>>  	psr->active = true;
>> @@ -255,11 +364,33 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder,
>>  	psr->encoder = encoder;
>>  	psr->set = psr_set;
>>  
>> +	psr->input_handler.event = psr_input_event;
>> +	psr->input_handler.connect = psr_input_connect;
>> +	psr->input_handler.disconnect = psr_input_disconnect;
>> +	psr->input_handler.name =
>> +		kasprintf(GFP_KERNEL, "rockchip-psr-%s", encoder->name);
>> +	if (!psr->input_handler.name) {
>> +		error = -ENOMEM;
>> +		goto err2;
>> +	}
>> +	psr->input_handler.id_table = psr_ids;
>> +	psr->input_handler.private = psr;
>> +
>> +	error = input_register_handler(&psr->input_handler);
>> +	if (error)
>> +		goto err1;
>> +
>>  	mutex_lock(&drm_drv->psr_list_lock);
>>  	list_add_tail(&psr->list, &drm_drv->psr_list);
>>  	mutex_unlock(&drm_drv->psr_list_lock);
>>  
>>  	return 0;
>> +
>> + err1:
>> +	kfree(psr->input_handler.name);
>> + err2:
>> +	kfree(psr);
>> +	return error;
>>  }
>>  EXPORT_SYMBOL(rockchip_drm_psr_register);
>>  
>> @@ -279,8 +410,11 @@ void rockchip_drm_psr_unregister(struct drm_encoder *encoder)
>>  	mutex_lock(&drm_drv->psr_list_lock);
>>  	list_for_each_entry_safe(psr, n, &drm_drv->psr_list, list) {
>>  		if (psr->encoder == encoder) {
>> +			input_unregister_handler(&psr->input_handler);
>>  			cancel_delayed_work_sync(&psr->flush_work);
>> +			cancel_work_sync(&psr->disable_work);
>>  			list_del(&psr->list);
>> +			kfree(psr->input_handler.name);
>>  			kfree(psr);
>>  		}
>>  	}
> 
>