Revert "[media] v4l: async: make v4l2 coexist with devicetree nodes in a dt overlay"
Subsystems (2)
PATCH 1/1 Revert "[media] v4l: async: make v4l2 coexist with devicetree nodes in a dt overlay"
This reverts commit d2180e0cf77dc7a7049671d5d57dfa0a228f83c1.
The commit was flawed in that if the device_node pointers are different, then in fact a different device is present and the device node could be different in ways other than full_name.
As Frank Rowand explained:
"When an overlay (1) is removed, all uses and references to the nodes and properties in that overlay are no longer valid. Any driver that uses any information from the overlay _must_ stop using any data from the overlay. Any driver that is bound to a new node in the overlay _must_ unbind. Any driver that became bound to a pre-existing node that was modified by the overlay (became bound after the overlay was applied) _must_ adjust itself to account for any changes to that node when the overlay is removed. One way to do this is to unbind when notified that the overlay is about to be removed, then to re-bind after the overlay is completely removed.
If an overlay (2) is subsequently applied, a node with the same full_name as from overlay (1) may exist. There is no guarantee that overlay (1) and overlay (2) are the same overlay, even if that node has the same full_name in both cases."
Also, there's not sufficient overlay support in mainline to actually remove and re-apply an overlay to hit this condition as overlays can only be applied from in kernel APIs.
---
Mauro, please apply this for 4.13. It could be marked for stable, too, but it's not going to apply cleanly with the fwnode changes.
Rob
drivers/media/v4l2-core/v4l2-async.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)
drivers/media/v4l2-core/v4l2-async.c +1 -6
@@ -44,12 +44,7 @@ static bool match_devname(struct v4l2_subdev *sd,static bool match_fwnode (struct v4l2_subdev *sd,struct v4l2_async_subdev *asd) { -if (!is_of_node (sd->fwnode) || !is_of_node (asd->match.fwnode.fwnode)) -return sd->fwnode == asd->match.fwnode.fwnode; - -return !of_node_cmp (of_node_full_name (to_of_node (sd->fwnode)), -of_node_full_name ( -to_of_node (asd->match.fwnode.fwnode))); +return sd->fwnode == asd->match.fwnode.fwnode; }static bool match_custom (struct v4l2_subdev *sd,struct v4l2_async_subdev *asd)
Signature · 1 line
2.11.0
Quoted 27 lines · Rob Herring
This reverts commit
d2180e0cf77dc7a7049671d5d57dfa0a228f83c1.The commit was flawed in that if the
device_nodepointers are different, then in fact a different device is present and the device node could be different in ways other thanfull_name.As Frank Rowand explained:
"When an overlay (1) is removed, all uses and references to the nodes and properties in that overlay are no longer valid. Any driver that uses any information from the overlay _must_ stop using any data from the overlay. Any driver that is bound to a new node in the overlay _must_ unbind. Any driver that became bound to a pre-existing node that was modified by the overlay (became bound after the overlay was applied) _must_ adjust itself to account for any changes to that node when the overlay is removed. One way to do this is to unbind when notified that the overlay is about to be removed, then to re-bind after the overlay is completely removed.
If an overlay (2) is subsequently applied, a node with the same
full_nameas from overlay (1) may exist. There is no guarantee that overlay (1) and overlay (2) are the same overlay, even if that node has the samefull_namein both cases."Also, there's not sufficient overlay support in mainline to actually remove and re-apply an overlay to hit this condition as overlays can only be applied from in kernel APIs.
Quoted 7 lines
Cc Mauro Carvalho Chehab <[email protected]>Cc Sakari Ailus <[email protected]>Cc Javi Merino <[email protected]>Cc Javier Martinez Canillas <[email protected]>Cc Sylwester Nawrocki <[email protected]>Cc Frank Rowand <[email protected]>Signed-off-by Rob Herring <[email protected]>
I've been trying to reproduce the original issues that I had for a couple of hours and I am not able to any more, so I can't object to the patch. The explanation from Frank Rowand is sound so:
Quoted 8 lines
---
Mauro, please apply this for 4.13. It could be marked for stable, too, but it's not going to apply cleanly with the fwnode changes.Rob
drivers/media/v4l2-core/v4l2-async.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)
Hi Rob,
Quoted 18 lines · Rob Herring
This reverts commit
d2180e0cf77dc7a7049671d5d57dfa0a228f83c1.The commit was flawed in that if the
device_nodepointers are different, then in fact a different device is present and the device node could be different in ways other thanfull_name.As Frank Rowand explained:
"When an overlay (1) is removed, all uses and references to the nodes and properties in that overlay are no longer valid. Any driver that uses any information from the overlay _must_ stop using any data from the overlay. Any driver that is bound to a new node in the overlay _must_ unbind. Any driver that became bound to a pre-existing node that was modified by the overlay (became bound after the overlay was applied) _must_ adjust itself to account for any changes to that node when the overlay is removed. One way to do this is to unbind when notified that the overlay is about to be removed, then to re-bind after the overlay is completely removed.
Quoted 4 lines
If an overlay (2) is subsequently applied, a node with the same
full_nameas from overlay (1) may exist. There is no guarantee that overlay (1) and overlay (2) are the same overlay, even if that node has the samefull_namein both cases."
The idea was that you could replace the DT snippet which is still referred to by another graph endpoint. This was risky as there was no guarantee that the stable endpoint configuration would still reflect the one that got replaced. But I guess with DT overlays you always have to know what you're doing.
Quoted 42 lines
Also, there's not sufficient overlay support in mainline to actually remove and re-apply an overlay to hit this condition as overlays can only be applied from in kernel APIs.
Cc Mauro Carvalho Chehab <[email protected]>Cc Sakari Ailus <[email protected]>Cc Javi Merino <[email protected]>Cc Javier Martinez Canillas <[email protected]>Cc Sylwester Nawrocki <[email protected]>Cc Frank Rowand <[email protected]>Signed-off-by Rob Herring <[email protected]>---
Mauro, please apply this for 4.13. It could be marked for stable, too, but it's not going to apply cleanly with the fwnode changes.Rob
drivers/media/v4l2-core/v4l2-async.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)drivers/media/v4l2-core/v4l2-async.c +1
-6@@ -44,12 +44,7 @@ static bool match_devname(struct v4l2_subdev *sd,static bool match_fwnode (struct v4l2_subdev *sd,struct v4l2_async_subdev *asd) { -if (!is_of_node (sd->fwnode) || !is_of_node (asd->match.fwnode.fwnode)) -return sd->fwnode == asd->match.fwnode.fwnode; - -return !of_node_cmp (of_node_full_name (to_of_node (sd->fwnode)), -of_node_full_name ( -to_of_node (asd->match.fwnode.fwnode))); +return sd->fwnode == asd->match.fwnode.fwnode; }static bool match_custom (struct v4l2_subdev *sd,struct v4l2_async_subdev *asd)Signature · 1 line
2.11.0
Signature · 4 lines
Regards, Sakari Ailus e-mail: [email protected] XMPP: [email protected]