| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.6 094/203] drm/fsl-dcu: use flat regmap cache | Date | Mon, 25 Jul 2016 13:55:09 -0700 |
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4.6-stable review patch. If anyone has any objections, please let me know.
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From: Stefan Agner <stefan@agner.ch>
commit ce492b3b8f99cf9d2f807ec22d8805c996a09503 upstream.
Using flat regmap cache instead of RB-tree to avoid the following lockdep warning on driver load: WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2755 lockdep_trace_alloc+0x15c/0x160() 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.
Use flat regmap cache and specify max register to be large enouth to cover all registers available in LS1021a and Vybrids register space.
Signed-off-by: Stefan Agner <stefan@agner.ch> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c @@ -40,9 +40,10 @@ static const struct regmap_config fsl_dc .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, + .max_register = 0x11fc, }; static int fsl_dcu_drm_irq_init(struct drm_device *dev)
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