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media: atomisp: reduce the risk of a race condition

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This driver is really on bad shape. One of the problems
is that, as soon as the I2C transfers start to happen, it
timeouts detecting a camera:

	ov2680 i2c-OVTI2680:00: ov2680_probe: ACPI detected it on bus ID=CAM1, HID=OVTI2680
	atomisp-isp2 0000:00:03.0: no camera attached or fail to detect
	ov2680 i2c-OVTI2680:00: gmin: initializing atomisp module subdev data using PMIC regulator
	...

The right fix here would be to use defer probe, but driver is
still on too bad shape.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Mauro Carvalho Chehab 2020-05-10 16:06:53 +02:00
parent d03f2e248c
commit 09d8746665
1 changed files with 23 additions and 2 deletions
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25
drivers/staging/media/atomisp/pci/atomisp_v4l2.c
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@ -46,6 +46,10 @@
#include "device_access.h"
/* Timeouts to wait for all subdevs to be registered */
#define SUBDEV_WAIT_TIMEOUT 50 /* ms */
#define SUBDEV_WAIT_TIMEOUT_MAX_COUNT 40 /* up to 2 seconds */
/* G-Min addition: pull this in from intel_mid_pm.h */
#define CSTATE_EXIT_LATENCY_C1 1
@ -1082,7 +1086,7 @@ static int atomisp_subdev_probe(struct atomisp_device *isp)
{
const struct atomisp_platform_data *pdata;
struct intel_v4l2_subdev_table *subdevs;
int ret, raw_index = -1;
int ret, raw_index = -1, count;
pdata = atomisp_get_platform_data();
if (!pdata) {
@ -1090,6 +1094,8 @@ static int atomisp_subdev_probe(struct atomisp_device *isp)
return 0;
}
/* FIXME: should, instead, use I2C probe */
for (subdevs = pdata->subdevs; subdevs->type; ++subdevs) {
struct v4l2_subdev *subdev;
struct i2c_board_info *board_info =
@ -1098,6 +1104,8 @@ static int atomisp_subdev_probe(struct atomisp_device *isp)
i2c_get_adapter(subdevs->v4l2_subdev.i2c_adapter_id);
int sensor_num, i;
dev_info(isp->dev, "Probing Subdev %s\n", board_info->type);
if (!adapter) {
dev_err(isp->dev,
"Failed to find i2c adapter for subdev %s\n",
@ -1177,6 +1185,16 @@ static int atomisp_subdev_probe(struct atomisp_device *isp)
}
}
/* FIXME: should return -EPROBE_DEFER if not all subdevs were probed */
for (count = 0; count < SUBDEV_WAIT_TIMEOUT_MAX_COUNT; count++) {
if (isp->input_cnt)
break;
msleep(SUBDEV_WAIT_TIMEOUT);
count++;
}
/* Wait more time to give more time for subdev init code */
msleep(5 * SUBDEV_WAIT_TIMEOUT);
/*
* HACK: Currently VCM belongs to primary sensor only, but correct
* approach must be to acquire from platform code which sensor
@ -1186,8 +1204,11 @@ static int atomisp_subdev_probe(struct atomisp_device *isp)
isp->inputs[raw_index].motor = isp->motor;
/* Proceed even if no modules detected. For COS mode and no modules. */
if (!isp->inputs[0].camera)
if (!isp->input_cnt)
dev_warn(isp->dev, "no camera attached or fail to detect\n");
else
dev_info(isp->dev, "detected %d camera sensors\n",
isp->input_cnt);
return atomisp_csi_lane_config(isp);
}