Unverified Commit f0fa69b5 authored by Derek Foreman's avatar Derek Foreman Committed by Maxime Ripard
Browse files

drm/connector: hdmi: Fix writing Dynamic Range Mastering infoframes 



The largest infoframe we create is the DRM (Dynamic Range Mastering)
infoframe which is 26 bytes + a 4 byte header, for a total of 30
bytes.

With HDMI_MAX_INFOFRAME_SIZE set to 29 bytes, as it is now, we
allocate too little space to pack a DRM infoframe in
write_device_infoframe(), leading to an ENOSPC return from
hdmi_infoframe_pack(), and never calling the connector's
write_infoframe() vfunc.

Instead of having HDMI_MAX_INFOFRAME_SIZE defined in two places,
replace HDMI_MAX_INFOFRAME_SIZE with HDMI_INFOFRAME_SIZE(MAX) and make
MAX 27 bytes - which is defined by the HDMI specification to be the
largest infoframe payload.

Fixes: f378b772 ("drm/connector: hdmi: Add Infoframes generation")
Fixes: c602e495 ("drm/connector: hdmi: Create Infoframe DebugFS entries")

Signed-off-by: default avatarDerek Foreman <derek.foreman@collabora.com>
Acked-by: default avatarMaxime Ripard <mripard@kernel.org>
Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240827163918.48160-1-derek.foreman@collabora.com


Signed-off-by: default avatarMaxime Ripard <mripard@kernel.org>
parent 440d52b3

drivers/gpu/drm/display/drm_hdmi_state_helper.c

+1 −3
Original line number Diff line number Diff line
@@ -521,8 +521,6 @@ int drm_atomic_helper_connector_hdmi_check(struct drm_connector *connector, 
}

EXPORT_SYMBOL(drm_atomic_helper_connector_hdmi_check);



#define HDMI_MAX_INFOFRAME_SIZE		29



static int clear_device_infoframe(struct drm_connector *connector,

				  enum hdmi_infoframe_type type)

{
@@ -563,7 +561,7 @@ static int write_device_infoframe(struct drm_connector *connector, 
{

	const struct drm_connector_hdmi_funcs *funcs = connector->hdmi.funcs;

	struct drm_device *dev = connector->dev;

	u8 buffer[HDMI_MAX_INFOFRAME_SIZE];

	u8 buffer[HDMI_INFOFRAME_SIZE(MAX)];

	int ret;

	int len;

drivers/gpu/drm/drm_debugfs.c

+1 −3
Original line number Diff line number Diff line
@@ -520,8 +520,6 @@ static const struct file_operations drm_connector_fops = { 
	.write = connector_write

};



#define HDMI_MAX_INFOFRAME_SIZE		29



static ssize_t

audio_infoframe_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos)

{
@@ -579,7 +577,7 @@ static ssize_t _f##_read_infoframe(struct file *filp, \ 
	struct drm_connector *connector; \

	union hdmi_infoframe *frame; \

	struct drm_device *dev; \

	u8 buf[HDMI_MAX_INFOFRAME_SIZE]; \

	u8 buf[HDMI_INFOFRAME_SIZE(MAX)]; \

	ssize_t len = 0; \

	\

	connector = filp->private_data; \

include/linux/hdmi.h

+9 −0
Original line number Diff line number Diff line
@@ -59,6 +59,15 @@ enum hdmi_infoframe_type { 
#define HDMI_DRM_INFOFRAME_SIZE    26

#define HDMI_VENDOR_INFOFRAME_SIZE  4



/*

 * HDMI 1.3a table 5-14 states that the largest InfoFrame_length is 27,

 * not including the packet header or checksum byte. We include the

 * checksum byte in HDMI_INFOFRAME_HEADER_SIZE, so this should allow

 * HDMI_INFOFRAME_SIZE(MAX) to be the largest buffer we could ever need

 * for any HDMI infoframe.

 */

#define HDMI_MAX_INFOFRAME_SIZE    27



#define HDMI_INFOFRAME_SIZE(type)	\

	(HDMI_INFOFRAME_HEADER_SIZE + HDMI_ ## type ## _INFOFRAME_SIZE)