The modeset lock protects the DDC code from concurrent modeset
operations, which use the same registers. Move that code from the
connector helpers into the DDC helpers .pre_xfer() and .post_xfer().
Both, .pre_xfer() and .post_xfer(), enclose the transfer of data blocks
over the I2C channel in the internal I2C function bit_xfer(). Both
calls are executed unconditionally if present. Invoking DDC transfers
from any where within the driver now takes the lock.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Reviewed-by: Sui Jingfeng <sui.jingfeng@xxxxxxxxx>
Reviewed-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
Tested-by: Sui Jingfeng <sui.jingfeng@xxxxxxxxx>
---
drivers/gpu/drm/ast/ast_ddc.c | 24 ++++++++++++++++++++++++
drivers/gpu/drm/ast/ast_mode.c | 30 ++++--------------------------
2 files changed, 28 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/ast/ast_ddc.c b/drivers/gpu/drm/ast/ast_ddc.c
index b84e656124f18..b7718084422f3 100644
--- a/drivers/gpu/drm/ast/ast_ddc.c
+++ b/drivers/gpu/drm/ast/ast_ddc.c
@@ -59,6 +59,28 @@ static void ast_ddc_algo_bit_data_setscl(void *data, int state)
}
}
+static int ast_ddc_algo_bit_data_pre_xfer(struct i2c_adapter *adapter)
+{
+ struct ast_ddc *ddc = i2c_get_adapdata(adapter);
+ struct ast_device *ast = ddc->ast;
+
+ /*
+ * Protect access to I/O registers from concurrent modesetting
+ * by acquiring the I/O-register lock.
+ */
+ mutex_lock(&ast->modeset_lock);
+
+ return 0;
+}
+
+static void ast_ddc_algo_bit_data_post_xfer(struct i2c_adapter *adapter)
+{
+ struct ast_ddc *ddc = i2c_get_adapdata(adapter);
+ struct ast_device *ast = ddc->ast;
+
+ mutex_unlock(&ast->modeset_lock);
+}
+
static int ast_ddc_algo_bit_data_getsda(void *data)
{
struct ast_ddc *ddc = data;
@@ -137,6 +159,8 @@ struct ast_ddc *ast_ddc_create(struct ast_device *ast)
bit->setscl = ast_ddc_algo_bit_data_setscl;
bit->getsda = ast_ddc_algo_bit_data_getsda;
bit->getscl = ast_ddc_algo_bit_data_getscl;
+ bit->pre_xfer = ast_ddc_algo_bit_data_pre_xfer;
+ bit->post_xfer = ast_ddc_algo_bit_data_post_xfer;
adapter->algo_data = bit;
ret = i2c_bit_add_bus(adapter);
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index fc73d3b65b2a1..8766a0f2eb3c7 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1346,30 +1346,19 @@ static int ast_crtc_init(struct drm_device *dev)
static int ast_vga_connector_helper_get_modes(struct drm_connector *connector)
{
- struct drm_device *dev = connector->dev;
- struct ast_device *ast = to_ast_device(dev);
struct edid *edid;
int count;
- /*
- * Protect access to I/O registers from concurrent modesetting
- * by acquiring the I/O-register lock.
- */
- mutex_lock(&ast->modeset_lock);
-
edid = drm_get_edid(connector, connector->ddc);
if (!edid)
- goto err_mutex_unlock;
-
- mutex_unlock(&ast->modeset_lock);
+ goto err_drm_get_edid;
count = drm_add_edid_modes(connector, edid);
kfree(edid);
return count;
-err_mutex_unlock:
- mutex_unlock(&ast->modeset_lock);
+err_drm_get_edid:
drm_connector_update_edid_property(connector, NULL);
return 0;
}
@@ -1444,30 +1433,19 @@ static int ast_vga_output_init(struct ast_device *ast)
static int ast_sil164_connector_helper_get_modes(struct drm_connector *connector)
{
- struct drm_device *dev = connector->dev;
- struct ast_device *ast = to_ast_device(dev);
struct edid *edid;
int count;
- /*
- * Protect access to I/O registers from concurrent modesetting
- * by acquiring the I/O-register lock.
- */
- mutex_lock(&ast->modeset_lock);
-
edid = drm_get_edid(connector, connector->ddc);
if (!edid)
- goto err_mutex_unlock;
-
- mutex_unlock(&ast->modeset_lock);
+ goto err_drm_get_edid;
count = drm_add_edid_modes(connector, edid);
kfree(edid);
return count;
-err_mutex_unlock:
- mutex_unlock(&ast->modeset_lock);
+err_drm_get_edid:
drm_connector_update_edid_property(connector, NULL);
return 0;
}
--
2.44.0
