On 01/20/2016 01:50 AM, Daniel Vetter wrote:
On Tue, Jan 19, 2016 at 09:00:40PM +0530, Kumar, Shobhit wrote:
On 01/19/2016 08:45 PM, Shobhit Kumar wrote:
INTEL_SOC_PMIC is loading later than I915 failing the gpiod_get and
pwm_get calls in i915. Add a retry to give time for the INTEL_SOC_PMIC
to load. This was fine till now but broke in latest kernel. Maybe load
time for the INTEL_SOC_PMIC has increased.
Since the lookup tables for GPIO (panel enable) and PWM both are
exported by same intel_soc_pmic driver, just retrying for the driver to
load in intel_dsi_init is sufficient. By the time we come to
setup_backlight, pwm would have been exported as well.
Maybe we should play with initcalls here but I was not sure how it will
impact if I change it for PMIC driver. IIRC, this discussion came up from
Daniel at the time of original patches also but somehow did not close
decidedly and has come back as a regression.
The correct way to handle this is to bail out with -EPROBE_DEFER. This is
how this is meant to be, no amount of random retrying will fix this
properly for such dynamic inter-module depencies.
Yeah, you are right, retries are working pretty randomly. I made a quick
changes all the way up to i915_driver_load returning -EPROBE_DEFER form
intel_setup_outputs and it seems to work.
And yes this is going to be a world-class test for our module load unwind
code.
Well it seems to be working :) Will have a cleaned up patch for review.
Also need to take care of this in the LPSS_PWM patches as well.
Regards
Shobhit
-Daniel
Regards
Shobhit
Signed-off-by: Shobhit Kumar <shobhit.kumar@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dsi.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 91cef35..e309ef6 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -1192,10 +1192,14 @@ void intel_dsi_init(struct drm_device *dev)
* Panel control.
*/
if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) {
+ int retry = 4;
+ do {
intel_dsi->gpio_panel =
gpiod_get(dev->dev, "panel", GPIOD_OUT_HIGH);
+ msleep(50);
+ } while (IS_ERR(intel_dsi->gpio_panel) && --retry);
- if (IS_ERR(intel_dsi->gpio_panel)) {
+ if (!retry) {
DRM_ERROR("Failed to own gpio for panel control\n");
intel_dsi->gpio_panel = NULL;
}
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