| Message ID | 20240823164621.385651-1-derek.foreman@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/connector: hdmi: Increase HDMI_MAX_INFOFRAME_SIZE to 30 | expand |
On Fri, 23 Aug 2024, Derek Foreman <derek.foreman@collabora.com> wrote: > 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. > > Increase HDMI_MAX_INFOFRAME_SIZE to 30 so we can successfully > write DRM infoframes. > > The drm_debugfs code is similarly updated. > > Signed-off-by: Derek Foreman <derek.foreman@collabora.com> Okay, thanks for the info. Looking into it, I think keeping this in two places and disconnected from the actual infoframe size definitions is hard to maintain. Maybe something like this: diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c index 7854820089ec..feb7a3a75981 100644 --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c @@ -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; diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c index 6b239a24f1df..9d3e6dd68810 100644 --- a/drivers/gpu/drm/drm_debugfs.c +++ b/drivers/gpu/drm/drm_debugfs.c @@ -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; \ diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h index 3bb87bf6bc65..3a442a59919e 100644 --- a/include/linux/hdmi.h +++ b/include/linux/hdmi.h @@ -59,6 +59,9 @@ enum hdmi_infoframe_type { #define HDMI_DRM_INFOFRAME_SIZE 26 #define HDMI_VENDOR_INFOFRAME_SIZE 4 +/* The biggest infoframe size */ +#define HDMI_MAX_INFOFRAME_SIZE HDMI_DRM_INFOFRAME_SIZE + #define HDMI_INFOFRAME_SIZE(type) \ (HDMI_INFOFRAME_HEADER_SIZE + HDMI_ ## type ## _INFOFRAME_SIZE) > --- > drivers/gpu/drm/display/drm_hdmi_state_helper.c | 2 +- > drivers/gpu/drm/drm_debugfs.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c > index 7854820089ec..cc7747d33fdf 100644 > --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c > +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c > @@ -521,7 +521,7 @@ 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 > +#define HDMI_MAX_INFOFRAME_SIZE 30 > > static int clear_device_infoframe(struct drm_connector *connector, > enum hdmi_infoframe_type type) > diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c > index 6b239a24f1df..3439fd65275a 100644 > --- a/drivers/gpu/drm/drm_debugfs.c > +++ b/drivers/gpu/drm/drm_debugfs.c > @@ -520,7 +520,7 @@ static const struct file_operations drm_connector_fops = { > .write = connector_write > }; > > -#define HDMI_MAX_INFOFRAME_SIZE 29 > +#define HDMI_MAX_INFOFRAME_SIZE 30 > > static ssize_t > audio_infoframe_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos)
diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c index 7854820089ec..cc7747d33fdf 100644 --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c @@ -521,7 +521,7 @@ 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 +#define HDMI_MAX_INFOFRAME_SIZE 30 static int clear_device_infoframe(struct drm_connector *connector, enum hdmi_infoframe_type type) diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c index 6b239a24f1df..3439fd65275a 100644 --- a/drivers/gpu/drm/drm_debugfs.c +++ b/drivers/gpu/drm/drm_debugfs.c @@ -520,7 +520,7 @@ static const struct file_operations drm_connector_fops = { .write = connector_write }; -#define HDMI_MAX_INFOFRAME_SIZE 29 +#define HDMI_MAX_INFOFRAME_SIZE 30 static ssize_t audio_infoframe_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos)
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. Increase HDMI_MAX_INFOFRAME_SIZE to 30 so we can successfully write DRM infoframes. The drm_debugfs code is similarly updated. Signed-off-by: Derek Foreman <derek.foreman@collabora.com> --- drivers/gpu/drm/display/drm_hdmi_state_helper.c | 2 +- drivers/gpu/drm/drm_debugfs.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)