So we can change the state while holding another spinlock (such as vblank_lock). Also add some locking around the flush function to ensure there are no races.
Signed-off-by: Sean Paul seanpaul@chromium.org --- drivers/gpu/drm/rockchip/rockchip_drm_psr.c | 54 +++++++++++++++++++++-------- 1 file changed, 39 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c index 6a51851..1fe271b 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c @@ -29,7 +29,7 @@ enum psr_state { struct psr_drv { struct list_head list; enum psr_state state; - struct mutex state_mutex; + spinlock_t lock;
struct timer_list flush_timer;
@@ -55,16 +55,33 @@ out: return psr; }
-static void psr_set_state(struct psr_drv *psr, enum psr_state state) +static void psr_set_state_locked(struct psr_drv *psr, enum psr_state state) { - mutex_lock(&psr->state_mutex); + /* + * Allowed finite state machine: + * + * PSR_ENABLE < = = = = = > PSR_FLUSH + * | ^ | + * | | | + * v | | + * PSR_DISABLE < - - - - - - - - - + */ + + /* Forbid no state change */ + if (state == psr->state) + return;
- if (psr->state == state) { - mutex_unlock(&psr->state_mutex); + /* Forbid DISABLE change to FLUSH */ + if (state == PSR_FLUSH && psr->state == PSR_DISABLE) return; - }
psr->state = state; + + /* Allow but no need hardware change, just need assign the state */ + if (state == PSR_DISABLE && psr->state == PSR_FLUSH) + return; + + /* Refact to hardware state change */ switch (state) { case PSR_ENABLE: psr->set(psr->encoder, true); @@ -74,19 +91,30 @@ static void psr_set_state(struct psr_drv *psr, enum psr_state state) case PSR_FLUSH: psr->set(psr->encoder, false); break; - }; + } +}
- mutex_unlock(&psr->state_mutex); +static void psr_set_state(struct psr_drv *psr, enum psr_state state) +{ + unsigned long flags; + + spin_lock_irqsave(&psr->lock, flags); + psr_set_state_locked(psr, state); + spin_unlock_irqrestore(&psr->lock, flags); }
static void psr_flush_handler(unsigned long data) { struct psr_drv *psr = (struct psr_drv *)data; + unsigned long flags;
- if (!psr || psr->state != PSR_FLUSH) + if (!psr) return;
- psr_set_state(psr, PSR_ENABLE); + spin_lock_irqsave(&psr->lock, flags); + if (psr->state == PSR_FLUSH) + psr_set_state_locked(psr, PSR_ENABLE); + spin_unlock_irqrestore(&psr->lock, flags); }
/** @@ -147,9 +175,6 @@ void rockchip_drm_psr_flush(struct drm_device *dev)
spin_lock_irqsave(&drm_drv->psr_list_lock, flags); list_for_each_entry(psr, &drm_drv->psr_list, list) { - if (psr->state == PSR_DISABLE) - continue; - mod_timer(&psr->flush_timer, round_jiffies_up(jiffies + PSR_FLUSH_TIMEOUT));
@@ -182,8 +207,7 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder, return -ENOMEM;
setup_timer(&psr->flush_timer, psr_flush_handler, (unsigned long)psr); - - mutex_init(&psr->state_mutex); + spin_lock_init(&psr->lock);
psr->state = PSR_DISABLE; psr->encoder = encoder;