On 7/8/22 17:07, Liviu Dudau wrote:
On Mon, Jun 06, 2022 at 12:47:13PM +0100, carsten.haitzler@xxxxxxxxxxxx wrote:
From: Carsten Haitzler <carsten.haitzler@xxxxxxx>
If something has already set up the DPU before the komeda driver comes
up, it will fail to init because it was just writing to the SRST bit in
the GCU control register and ignoring others. This resulted in TBU
bringup stalling and init failing. By writing completely we also set the
mode back to 0 (inactive) too and thus TBU bringup works.
This is a rather large hammer, tbh. I would like to see if there is a better way of
handling the handover from EFIFB that this patch is trying to fix, but I lack an
usable plaform for that. It will generate a flicker at module load time, but if users
of Morello are happy with that, then
Just FYI - it'll flicker anyway as the PHY is external and gets
re-initted etc. anyway... This also happens to handle the situation
where something goes wrong and you have an already initted komeda sue to
a previous module load (and it's still alive and working due to an
unclean shutdown). It'll allow you to load the module again :) So it's
multi-useful.
Acked-by: Liviu Dudau <liviu.dudau@xxxxxxx>
Best regards,
Liviu
Signed-off-by: Carsten Haitzler <carsten.haitzler@xxxxxxx>
---
drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c b/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c
index 00fa56c29b3e..39618c1a4c81 100644
--- a/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c
+++ b/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c
@@ -309,8 +309,7 @@ static int d71_reset(struct d71_dev *d71)
u32 __iomem *gcu = d71->gcu_addr;
int ret;
- malidp_write32_mask(gcu, BLK_CONTROL,
- GCU_CONTROL_SRST, GCU_CONTROL_SRST);
+ malidp_write32(gcu, BLK_CONTROL, GCU_CONTROL_SRST);
ret = dp_wait_cond(!(malidp_read32(gcu, BLK_CONTROL) & GCU_CONTROL_SRST),
100, 1000, 10000);
--
2.32.0
