Some integrated ATI Radeon chipset implementations
(e. g. Asus M2A-VM HDMI) indicate the availability
of a DDC even when there's no monitor connected.
In this case, drm_get_edid and drm_edid_block_valid
periodically dump data and kernel errors into system
log files and onto terminals, which lead to an unacceptable
system behaviour.
Tested since kernel 2.35 on Asus M2A-VM HDMI board
Signed-off-by: Thomas Reim <rdratlos@xxxxxxxxxxx>
---
drivers/gpu/drm/radeon/radeon_connectors.c | 10 +++++
drivers/gpu/drm/radeon/radeon_display.c | 11 +++++
drivers/gpu/drm/radeon/radeon_i2c.c | 60 ++++++++++++++++++++++++++++
drivers/gpu/drm/radeon/radeon_mode.h | 1 +
4 files changed, 82 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index cbfca3a..7a76e45 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -828,6 +828,16 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
if (radeon_connector->ddc_bus)
dret = radeon_ddc_probe(radeon_connector);
+
+ /* Asus M2A-VM HDMI DDC quirk:
+ * Some integrated ATI Radeon chipset implementations (e. g. Asus
+ * M2A-VM HDMI) indicate the availability of a DDC even when there's
+ * no monitor connected.The following check prevents drm_get_edid()
+ * and drm_edid_block_valid() of periodically dumping data and kernel
+ * errors into the logs and onto the terminal, which would lead to an
+ * unacceptable system behaviour */
+ if (dret && connector->connector_type == DRM_MODE_CONNECTOR_HDMIA)
+ dret = radeon_ddc_edid_probe(radeon_connector);
if (dret) {
if (radeon_connector->edid) {
kfree(radeon_connector->edid);
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 292f73f..550f143 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -715,6 +715,9 @@ static bool radeon_setup_enc_conn(struct drm_device *dev)
if (ret) {
radeon_setup_encoder_clones(dev);
radeon_print_display_setup(dev);
+ /* Is this really required here?
+ Seems to just force drm to dump EDID errors
+ to kernel logs */
list_for_each_entry(drm_connector, &dev->mode_config.connector_list, head)
radeon_ddc_dump(drm_connector);
}
@@ -777,8 +780,16 @@ static int radeon_ddc_dump(struct drm_connector *connector)
if (!radeon_connector->ddc_bus)
return -1;
edid = drm_get_edid(connector, &radeon_connector->ddc_bus->adapter);
+ /* Asus M2A-VM HDMI DDC quirk: Log EDID retrieval status here once,
+ * instead of periodically dumping data and kernel errors into the
+ * logs, if a monitor is not connected to HDMI */
if (edid) {
+ DRM_INFO("Radeon display connector %s: Found valid EDID",
+ drm_get_connector_name(connector));
kfree(edid);
+ } else {
+ DRM_INFO("Radeon display connector %s: No display connected or invalid EDID",
+ drm_get_connector_name(connector));
}
return ret;
}
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index 781196d..1d6decd 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -63,6 +63,66 @@ bool radeon_ddc_probe(struct radeon_connector *radeon_connector)
return false;
}
+/**
+ * Probe EDID information via I2C.
+ *
+ * \param adapter : i2c device adaptor
+ * \param buf : EDID data buffer to be filled
+ * \param len : EDID data buffer length
+ * \return 0 on success or -1 on failure.
+ *
+ * Try to fetch EDID information by calling i2c driver function and
+ * probe for EDID header information.
+ *
+ * Remark:
+ * This function has been added, because there are integrated ATI Radeon
+ * chipset implementations (e. g. Asus M2A-VM HDMI that indicate the
+ * availability of a DDC even when there's no monitor connected.
+ * In this case, drm_get_edid and drm_edid_block_valid periodically dump
+ * data and kernel errors into the logs and onto the terminal, which lead to
+ * an unacceptable system behaviour.
+ */
+bool radeon_ddc_edid_probe(struct radeon_connector *radeon_connector)
+{
+ u8 out_buf[] = { 0x0, 0x0};
+ u8 block[20];
+ int ret;
+ struct i2c_msg msgs[] = {
+ {
+ .addr = 0x50,
+ .flags = 0,
+ .len = 1,
+ .buf = out_buf,
+ }, {
+ .addr = 0x50,
+ .flags = I2C_M_RD,
+ .len = 20,
+ .buf = block,
+ }
+ };
+
+ ret = i2c_transfer(&radeon_connector->ddc_bus->adapter, msgs, 2);
+ if (ret == 2)
+ if ((block[0] == 0x00) &&
+ (block[7] == 0x00) &&
+ (block[1] == 0xff) &&
+ (block[2] == 0xff) &&
+ (block[3] == 0xff) &&
+ (block[4] == 0xff) &&
+ (block[5] == 0xff) &&
+ (block[6] == 0xff))
+ /* EDID header starts with:
+ * 0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x00;
+ * seems to be an EDID */
+ if ((block[18] != 0x00) || (block[19] != 0x00))
+ /* EDID headers end with EDID version and
+ * revision number: EDID version is not 0.0 =>
+ * EDID should be available */
+ return true;
+ /* Couldn't find an accessible EDID on this connector. */
+ return false;
+}
+
/* bit banging i2c */
static void radeon_i2c_do_lock(struct radeon_i2c_chan *i2c, int lock_state)
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 6df4e3c..14710fc 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -515,6 +515,7 @@ extern void radeon_i2c_put_byte(struct radeon_i2c_chan *i2c,
extern void radeon_router_select_ddc_port(struct radeon_connector *radeon_connector);
extern void radeon_router_select_cd_port(struct radeon_connector *radeon_connector);
extern bool radeon_ddc_probe(struct radeon_connector *radeon_connector);
+extern bool radeon_ddc_edid_probe(struct radeon_connector *radeon_connector);
extern int radeon_ddc_get_modes(struct radeon_connector *radeon_connector);
extern struct drm_encoder *radeon_best_encoder(struct drm_connector *connector);
--
1.7.1
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