On 2016-01-20 18:50, Stefan Agner wrote:
Using flat regmap cache instead of RB-tree to avoid the following lockdep warning on driver load: [ 0.697285] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2755 lockdep_trace_alloc+0x15c/0x160() [ 0.697449] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
The RB-tree regmap cache needs to allocate new space on first writes. However, allocations in an atomic context (e.g. when a spinlock is held) are not allowed. The function regmap_write calls map->lock, which acquires a spinlock in the fast_io case. Since the FSL DCU driver uses MMIO, the regmap bus of type regmap_mmio is being used which has fast_io set to true.
The MMIO space of the DCU driver is reasonable condense, hence using the much faster flat regmap cache is anyway the better choice.
Signed-off-by: Stefan Agner stefan@agner.ch Cc: Mark Brown broonie@kernel.org
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 20 ++++++++++++-------- drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h | 6 ++++-- 2 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c index e01c813..971c520 100644 --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c @@ -36,11 +36,11 @@ static bool fsl_dcu_drm_is_volatile_reg(struct device *dev, unsigned int reg) return false; }
-static const struct regmap_config fsl_dcu_regmap_config = { +static struct regmap_config fsl_dcu_regmap_config = { .reg_bits = 32, .reg_stride = 4, .val_bits = 32,
- .cache_type = REGCACHE_RBTREE,
.cache_type = REGCACHE_FLAT,
.volatile_reg = fsl_dcu_drm_is_volatile_reg,
}; @@ -260,12 +260,14 @@ static const struct fsl_dcu_soc_data fsl_dcu_ls1021a_data = { .name = "ls1021a", .total_layer = 16, .max_layer = 4,
- .max_register = LS1021A_DCU_MAX_REGISTER,
};
static const struct fsl_dcu_soc_data fsl_dcu_vf610_data = { .name = "vf610", .total_layer = 64, .max_layer = 6,
- .max_register = VF610_DCU_MAX_REGISTER,
};
static const struct of_device_id fsl_dcu_of_match[] = { @@ -331,6 +333,14 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev) return ret; }
- id = of_match_node(fsl_dcu_of_match, pdev->dev.of_node);
- if (!id)
return -ENODEV;- drm = drm_dev_alloc(driver, dev);
- fsl_dev->soc = id->data;
- fsl_dcu_regmap_config.max_register = fsl_dev->soc->max_register; fsl_dev->regmap = devm_regmap_init_mmio(dev, base, &fsl_dcu_regmap_config); if (IS_ERR(fsl_dev->regmap)) {
@@ -338,12 +348,6 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev) return PTR_ERR(fsl_dev->regmap); }
- id = of_match_node(fsl_dcu_of_match, pdev->dev.of_node);
- if (!id)
return -ENODEV;- fsl_dev->soc = id->data;
- drm = drm_dev_alloc(driver, dev); if (!drm) return -ENOMEM;
The drm_dev_alloc call should be close to its error handling, and moving is anyway not necessary...
Will fix that in v2
-- Stefan
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h index 2a724f3..7c296a0 100644 --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h @@ -114,8 +114,6 @@ #define DCU_UPDATE_MODE_MODE BIT(31) #define DCU_UPDATE_MODE_READREG BIT(30)
-#define DCU_DCFB_MAX 0x300
#define DCU_CTRLDESCLN(layer, reg) (0x200 + (reg - 1) * 4 + (layer) * 0x40)
#define DCU_LAYER_HEIGHT(x) ((x) << 16) @@ -155,6 +153,9 @@ #define DCU_LAYER_POST_SKIP(x) ((x) << 16) #define DCU_LAYER_PRE_SKIP(x) (x)
+#define VF610_DCU_MAX_REGISTER 0x11fc +#define LS1021A_DCU_MAX_REGISTER 0x5fc
#define FSL_DCU_RGB565 4 #define FSL_DCU_RGB888 5 #define FSL_DCU_ARGB8888 6 @@ -175,6 +176,7 @@ struct fsl_dcu_soc_data { unsigned int total_layer; /*max layer number DCU supported*/ unsigned int max_layer;
- unsigned int max_register;
};
struct fsl_dcu_drm_device {