Re: [PATCH 10/10] drm: crc: Introduce pre_crc_read function

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org, Mahesh Kumar <mahesh1.kumar@intel.com>
Subject: Re: [PATCH 10/10] drm: crc: Introduce pre_crc_read function
Date: Tue, 10 Jul 2018 15:05:23 +0300	[thread overview]
Message-ID: <8062596.8OoQM1OII8@avalon> (raw)
In-Reply-To: <20180702110729.8171-11-mahesh1.kumar@intel.com>

Hi Mahesh,

Thank you for the patch.

On Monday, 2 July 2018 14:07:29 EEST Mahesh Kumar wrote:
> This patch implements a callback function "pre_crc_read" which will
> be called before crc read. In this function driver can implement and
> preparation work required for successfully reading CRC data.

Reviewing this is difficult with a user. Could you submit a patch that makes 
use of this callback in a driver ?

> Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
> Cc: dri-devel@lists.freedesktop.org
> ---
>  drivers/gpu/drm/drm_debugfs_crc.c |  8 ++++++++
>  include/drm/drm_crtc.h            | 14 ++++++++++++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_debugfs_crc.c
> b/drivers/gpu/drm/drm_debugfs_crc.c index add35b77165b..7aeed89f934a 100644
> --- a/drivers/gpu/drm/drm_debugfs_crc.c
> +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> @@ -272,6 +272,14 @@ static ssize_t crtc_crc_read(struct file *filep, char
> __user *user_buf, return 0;
>  	}
> 
> +	if (crtc->funcs->pre_crc_read) {
> +		ret = crtc->funcs->pre_crc_read(crtc);
> +		if (ret) {
> +			spin_unlock_irq(&crc->lock);
> +			return ret;
> +		}
> +	}
> +
>  	/* Nothing to read? */
>  	while (crtc_crc_data_count(crc) == 0) {
>  		if (filep->f_flags & O_NONBLOCK) {
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 81780325f36f..7e2eab9c2f52 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -691,6 +691,20 @@ struct drm_crtc_funcs {
>  	 */
>  	const char *const *(*get_crc_sources)(struct drm_crtc *crtc,
>  					      size_t *count);
> +	/**
> +	 * @pre_crc_read:
> +	 *
> +	 * Driver callback for performing any preparation work required by
> +	 * driver before reading CRC
> +	 *
> +	 * This callback is optional if the driver does not support CRC
> +	 * generation or no prework is required before reading the crc
> +	 *
> +	 * RETURNS:
> +	 *
> +	 * 0 on success or a negative error code on failure.
> +	 */
> +	int (*pre_crc_read)(struct drm_crtc *crtc);
> 
>  	/**
>  	 * @atomic_print_state:

-- 
Regards,

Laurent Pinchart

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