Mali DP500 operates in continuous writeback mode (writes frame content until stopped) and it needs special handling in order to behave like a one-shot writeback engine. The original state machine added for DP500 was a bit fragile, as it did not handle correctly cases where a new atomic commit was in progress when the SE IRQ happens and it would commit some partial updates.
Improve the handling by adding a parameter to the set_config_valid() function to clear the config valid bit in hardware before starting a new commit and by introducing a MW_RESTART state in the writeback state machine to cater for the case where a new writeback commit gets submitted while the last one is still being active.
Reported-by: Brian Starkey brian.starkey@arm.com Reviewed-by: Brian Starkey brian.starkey@arm.com Signed-off-by: Liviu Dudau liviu.dudau@arm.com --- drivers/gpu/drm/arm/malidp_drv.c | 3 ++- drivers/gpu/drm/arm/malidp_hw.c | 39 +++++++++++++++++++++++--------- drivers/gpu/drm/arm/malidp_hw.h | 11 +++++---- 3 files changed, 36 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c index fc264554c5035..83e8f911f1579 100644 --- a/drivers/gpu/drm/arm/malidp_drv.c +++ b/drivers/gpu/drm/arm/malidp_drv.c @@ -171,7 +171,7 @@ static int malidp_set_and_wait_config_valid(struct drm_device *drm) struct malidp_hw_device *hwdev = malidp->dev; int ret;
- hwdev->hw->set_config_valid(hwdev); + hwdev->hw->set_config_valid(hwdev, 1); /* don't wait for config_valid flag if we are in config mode */ if (hwdev->hw->in_config_mode(hwdev)) { atomic_set(&malidp->config_valid, MALIDP_CONFIG_VALID_DONE); @@ -230,6 +230,7 @@ static void malidp_atomic_commit_tail(struct drm_atomic_state *state) * know that we are updating registers */ atomic_set(&malidp->config_valid, MALIDP_CONFIG_START); + malidp->dev->hw->set_config_valid(malidp->dev, 0);
drm_atomic_helper_commit_modeset_disables(drm, state);
diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c index e0de7a35a0beb..8759f90c313d9 100644 --- a/drivers/gpu/drm/arm/malidp_hw.c +++ b/drivers/gpu/drm/arm/malidp_hw.c @@ -27,7 +27,8 @@ enum { MW_NOT_ENABLED = 0, /* SE writeback not enabled */ MW_ONESHOT, /* SE in one-shot mode for writeback */ MW_START, /* SE started writeback */ - MW_STOP, /* SE finished writeback */ + MW_RESTART, /* SE will start another writeback after this one */ + MW_STOP, /* SE needs to stop after this writeback */ };
static const struct malidp_format_id malidp500_de_formats[] = { @@ -231,9 +232,12 @@ static bool malidp500_in_config_mode(struct malidp_hw_device *hwdev) return false; }
-static void malidp500_set_config_valid(struct malidp_hw_device *hwdev) +static void malidp500_set_config_valid(struct malidp_hw_device *hwdev, u8 value) { - malidp_hw_setbits(hwdev, MALIDP_CFG_VALID, MALIDP500_CONFIG_VALID); + if (value) + malidp_hw_setbits(hwdev, MALIDP_CFG_VALID, MALIDP500_CONFIG_VALID); + else + malidp_hw_clearbits(hwdev, MALIDP_CFG_VALID, MALIDP500_CONFIG_VALID); }
static void malidp500_modeset(struct malidp_hw_device *hwdev, struct videomode *mode) @@ -386,7 +390,11 @@ static int malidp500_enable_memwrite(struct malidp_hw_device *hwdev, /* enable the scaling engine block */ malidp_hw_setbits(hwdev, MALIDP_SCALE_ENGINE_EN, de_base + MALIDP_DE_DISPLAY_FUNC);
- hwdev->mw_state = MW_START; + /* restart the writeback if already enabled */ + if (hwdev->mw_state != MW_NOT_ENABLED) + hwdev->mw_state = MW_RESTART; + else + hwdev->mw_state = MW_START;
malidp_hw_write(hwdev, fmt_id, base + MALIDP_MW_FORMAT); switch (num_planes) { @@ -415,7 +423,7 @@ static void malidp500_disable_memwrite(struct malidp_hw_device *hwdev) { u32 base = malidp_get_block_base(hwdev, MALIDP_DE_BLOCK);
- if (hwdev->mw_state == MW_START) + if (hwdev->mw_state == MW_START || hwdev->mw_state == MW_RESTART) hwdev->mw_state = MW_STOP; malidp_hw_clearbits(hwdev, MALIDP_SE_MEMWRITE_EN, MALIDP500_SE_CONTROL); malidp_hw_clearbits(hwdev, MALIDP_SCALE_ENGINE_EN, base + MALIDP_DE_DISPLAY_FUNC); @@ -500,9 +508,12 @@ static bool malidp550_in_config_mode(struct malidp_hw_device *hwdev) return false; }
-static void malidp550_set_config_valid(struct malidp_hw_device *hwdev) +static void malidp550_set_config_valid(struct malidp_hw_device *hwdev, u8 value) { - malidp_hw_setbits(hwdev, MALIDP_CFG_VALID, MALIDP550_CONFIG_VALID); + if (value) + malidp_hw_setbits(hwdev, MALIDP_CFG_VALID, MALIDP550_CONFIG_VALID); + else + malidp_hw_clearbits(hwdev, MALIDP_CFG_VALID, MALIDP550_CONFIG_VALID); }
static void malidp550_modeset(struct malidp_hw_device *hwdev, struct videomode *mode) @@ -1004,15 +1015,21 @@ static irqreturn_t malidp_se_irq(int irq, void *arg) /* disable writeback after stop */ hwdev->mw_state = MW_NOT_ENABLED; break; + case MW_RESTART: + drm_writeback_signal_completion(&malidp->mw_connector, 0); + /* fall through to a new start */ case MW_START: /* writeback started, need to emulate one-shot mode */ hw->disable_memwrite(hwdev); /* - * only set config_valid HW bit if there is no - * other update in progress + * only set config_valid HW bit if there is no other update + * in progress or if we raced ahead of the DE IRQ handler + * and config_valid flag will not be update until later */ - if (atomic_read(&malidp->config_valid) != MALIDP_CONFIG_START) - hw->set_config_valid(hwdev); + status = malidp_hw_read(hwdev, hw->map.dc_base + MALIDP_REG_STATUS); + if ((atomic_read(&malidp->config_valid) != MALIDP_CONFIG_START) || + (status & hw->map.dc_irq_map.vsync_irq)) + hw->set_config_valid(hwdev, 1); break; } } diff --git a/drivers/gpu/drm/arm/malidp_hw.h b/drivers/gpu/drm/arm/malidp_hw.h index c479738b81af5..bd41aa6974a06 100644 --- a/drivers/gpu/drm/arm/malidp_hw.h +++ b/drivers/gpu/drm/arm/malidp_hw.h @@ -152,12 +152,13 @@ struct malidp_hw { bool (*in_config_mode)(struct malidp_hw_device *hwdev);
/* - * Set configuration valid flag for hardware parameters that can - * be changed outside the configuration mode. Hardware will use - * the new settings when config valid is set after the end of the - * current buffer scanout + * Set/clear configuration valid flag for hardware parameters that can + * be changed outside the configuration mode to the given value. + * Hardware will use the new settings when config valid is set, + * after the end of the current buffer scanout, and will ignore + * any new values for those parameters if config valid flag is cleared */ - void (*set_config_valid)(struct malidp_hw_device *hwdev); + void (*set_config_valid)(struct malidp_hw_device *hwdev, u8 value);
/* * Set a new mode in hardware. Requires the hardware to be in