Hi Thomas,
Do you have other suggestion for this patch??
Please kindly advise.
On 2023/4/25 下午 03:39, Jammy Huang wrote:
Hi Thomas,
I think DP501 is OK. It doesn't use ioregs in ast_dp501_read_edid().
On 2023/4/25 下午 03:27, Thomas Zimmermann wrote:
Hi
Am 25.04.23 um 09:03 schrieb Jammy Huang:
If we switch display and update cursor together, it could lead to
modeset failed because of concurrent access to IO registers.
Add lock protection in DP's edid access to avoid this problem.
Thanks for the patch. I thought I fixed this issue already, but that
apparently only happened for SIL164 and VGA.
What about ast_dp501_connector_helper_get_modes()? Does it require
the locking as well?
Signed-off-by: Jammy Huang <jammy_huang@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/ast/ast_mode.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/gpu/drm/ast/ast_mode.c
b/drivers/gpu/drm/ast/ast_mode.c
index 984ec590a7e7..fe5f1fd61361 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1635,6 +1635,8 @@ static int ast_dp501_output_init(struct
ast_private *ast)
static int ast_astdp_connector_helper_get_modes(struct
drm_connector *connector)
{
void *edid;
+ struct drm_device *dev = connector->dev;
+ struct ast_private *ast = to_ast_private(dev);
We've meanwhile renamed ast_private to ast_device. Could you please
provide an updated patch for the drm-misc-next tree?
Best regards
Thomas
int succ;
int count;
@@ -1643,10 +1645,18 @@ static int
ast_astdp_connector_helper_get_modes(struct drm_connector *connector)
if (!edid)
goto err_drm_connector_update_edid_property;
+ /*
+ * Protect access to I/O registers from concurrent modesetting
+ * by acquiring the I/O-register lock.
+ */
+ mutex_lock(&ast->ioregs_lock);
+
succ = ast_astdp_read_edid(connector->dev, edid);
if (succ < 0)
goto err_kfree;
+ mutex_unlock(&ast->ioregs_lock);
+
drm_connector_update_edid_property(connector, edid);
count = drm_add_edid_modes(connector, edid);
kfree(edid);
@@ -1654,6 +1664,7 @@ static int
ast_astdp_connector_helper_get_modes(struct drm_connector *connector)
return count;
err_kfree:
+ mutex_unlock(&ast->ioregs_lock);
kfree(edid);
err_drm_connector_update_edid_property:
drm_connector_update_edid_property(connector, NULL);
base-commit: 61d325dcbc05d8fef88110d35ef7776f3ac3f68b
--
Best Regards
Jammy
