[PATCH v2 02/10] drm/bochs: Use helpers for struct drm_edid

[Dmitry Baryshkov]

On Mon, Sep 02, 2024 at 12:53:40PM GMT, Thomas Zimmermann wrote:
> Implement a read function for struct drm_edid and read the EDID data
> with drm_edit_read_custom(). Update the connector data accordingly.
> 
> The EDID data comes from the emulator itself and the connector stores
> a copy in its EDID property. The drm_edid field in struct bochs_device
> is therefore not required. Remove it.
> 
> If qemu provides no EDID data, install default display modes as before.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Acked-by: Gerd Hoffmann <kraxel at redhat.com>
> ---
>  drivers/gpu/drm/tiny/bochs.c | 48 +++++++++++++++++-------------------
>  1 file changed, 22 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
> index 47a45a14306c..197fc00b373f 100644
> --- a/drivers/gpu/drm/tiny/bochs.c
> +++ b/drivers/gpu/drm/tiny/bochs.c
> @@ -85,7 +85,6 @@ struct bochs_device {
>  	u16 yres_virtual;
>  	u32 stride;
>  	u32 bpp;
> -	const struct drm_edid *drm_edid;
>  
>  	/* drm */
>  	struct drm_device *dev;
> @@ -172,12 +171,14 @@ static void bochs_hw_set_little_endian(struct bochs_device *bochs)
>  #define bochs_hw_set_native_endian(_b) bochs_hw_set_little_endian(_b)
>  #endif
>  
> -static int bochs_get_edid_block(void *data, u8 *buf,
> -				unsigned int block, size_t len)
> +static int bochs_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
>  {
>  	struct bochs_device *bochs = data;
>  	size_t i, start = block * EDID_LENGTH;
>  
> +	if (!bochs->mmio)
> +		return -1;
> +
>  	if (start + len > 0x400 /* vga register offset */)
>  		return -1;
>  
> @@ -187,25 +188,20 @@ static int bochs_get_edid_block(void *data, u8 *buf,
>  	return 0;
>  }
>  
> -static int bochs_hw_load_edid(struct bochs_device *bochs)
> +static const struct drm_edid *bochs_hw_read_edid(struct drm_connector *connector)
>  {
> +	struct drm_device *dev = connector->dev;
> +	struct bochs_device *bochs = dev->dev_private;
>  	u8 header[8];
>  
> -	if (!bochs->mmio)
> -		return -1;
> -
>  	/* check header to detect whenever edid support is enabled in qemu */
>  	bochs_get_edid_block(bochs, header, 0, ARRAY_SIZE(header));
>  	if (drm_edid_header_is_valid(header) != 8)

I understand that you probably don't want to change the behaviour of the
driver, but maybe it's better to check drm_edid_read_custom return
value? Bochs, amdgpu and radeon are the only drivers that call
drm_edid_header_is_valid().

> -		return -1;
> +		return NULL;
>  

-- 
With best wishes
Dmitry