On 2014년 11월 07일 17:29, Andrzej Hajda wrote:
On 11/06/2014 03:10 PM, Inki Dae wrote:
This patch resovles the infinite loop issue incurred when Exyno drm driver is enabled but all kms drivers are disabled on Exynos board by returning -EPROBE_DEFER only in case that there is kms device registered.
There are many different cases it can still fail:
- there are no matching device nodes in DT,
With this patch, -ENODEV would be returned instead of -EPROBE_DEFER in above case. So it should be no problem.
- some devices are present in DT, some drivers are enabled,
but they do not match,
Right.
- even if there exists some pairs device_node-driver it can fail -
exynos_drm_match_add requires higher level matches - every crtc should have matching encoder.
Also right.
I think even super-node will not solve all these issues.
With the super device node, my intention is that we can remove unnecessary exception codes like of_machine_is_compatible functions. So the use of the super device node wouldn't be relevant to this issue.
The real problem here is that during probe of exynos_drm ipp driver is successfully probed and after that exynos_drm probe fails, which causes also removing ipp, anyway successful ipp probe triggers whole re-probe mechanism again. It creates infinite loop.
The problem is not because of only IPP driver. In all cases that non kms drivers are enabled and they are probed.
I think moving exynos_platform_device_ipp_register after component_master_add_with_match should solve some of the issue,
g2d also should be moved.
but I guess it could create new ones, or maybe not, needs checking.
On the other side I wonder if we really need to have ipp device at all, replacing it with helpers of exynos_drm should be possible, I guess.
Agree. I also think that we don't really need IPP driver. Instead, we can register post processor drivers - fimc, rotator, and gscaler - directly without IPP driver like g2d did.
Thanks, Inki Dae
Regards Andrzej
Signed-off-by: Inki Dae inki.dae@samsung.com
drivers/gpu/drm/exynos/exynos_drm_drv.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c index ecc86aa..14c6af7 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c @@ -488,6 +488,12 @@ static struct component_match *exynos_drm_match_add(struct device *dev)
mutex_lock(&drm_component_lock);
- /* Do not retry to probe if there is no any kms driver regitered. */
- if (list_empty(&drm_component_list)) {
mutex_unlock(&drm_component_lock);return ERR_PTR(-ENODEV);- }
- list_for_each_entry(cdev, &drm_component_list, list) { /*
- Add components to master only in case that crtc and
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