On 3/7/2019 3:02 PM, Abhinav Kumar wrote:
On 2019-03-07 13:59, Sean Paul wrote:
On Wed, Mar 06, 2019 at 05:28:54PM -0800, Abhinav Kumar wrote:
When panel probe happens after DSI probe, the DSI probe
is deferred as per current design. In the probe defer path
dsi device is destroyed. This NULL dsi device could be
deferenced by the panel probe in the mipi_dsi_attach path.
Check for NULL dsi device before accessing it.
It would be really nice to sort all of this out in a manner that's not
sprinkling NULL checks around the driver. I spent 5 minutes looking
around and
couldn't really make sense of how all of these pieces interact, but
this seems
like it might be an architectural problem (perhaps since dpu was using
its own
panel stuff instead of drm_panel?).
Anyways, it'd be nice to fix that.
In the meantime, could you please add a big comment like the !dev
check in this
function explaining how this situation can come to pass? That way the
knowledge
isn't lost and whoever comes along to clean up all of these probe
checks will
have some clue as to what's going on.
Sean
[Abhinav] Sure Sean, will add a detailed comment to explain the scenario
Abhinav, it looks like this may have dropped off your radar. Do you
know when you'll come back to it?
Reported-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
Tested-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
Signed-off-by: Abhinav Kumar <abhinavk@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c
b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index 80aa634..cc2569d 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
@@ -769,7 +769,7 @@ bool msm_dsi_manager_cmd_xfer_trigger(int id, u32
dma_base, u32 len)
void msm_dsi_manager_attach_dsi_device(int id, u32 device_flags)
{
struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
- struct drm_device *dev = msm_dsi->dev;
+ struct drm_device *dev = msm_dsi ? msm_dsi->dev : NULL;
struct msm_drm_private *priv;
struct msm_kms *kms;
struct drm_encoder *encoder;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
--
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
