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Commit 263c3b80 authored by Lucas Stach's avatar Lucas Stach Committed by Philipp Zabel
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gpu: ipu-v3: prg: wait for double buffers to be filled on channel startup 



Wait for both double buffer to be filled when first starting a channel.
This makes channel startup a lot more reliable, probably because it allows
the internal state machine to settle before the requests from the IPU are
coming in.

Signed-off-by: default avatarLucas Stach <l.stach@pengutronix.de>
[p.zabel@pengutronix.de: rebased before switch to runtime PM]
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
parent cda77556

drivers/gpu/ipu-v3/ipu-prg.c

+7 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <drm/drm_fourcc.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/iopoll.h>

#include <linux/mfd/syscon.h>

#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>

#include <linux/module.h>
@@ -329,6 +330,12 @@ int ipu_prg_channel_configure(struct ipuv3_channel *ipu_chan, 
	val = IPU_PRG_REG_UPDATE_REG_UPDATE;

	writel(val, prg->regs + IPU_PRG_REG_UPDATE);



	/* wait for both double buffers to be filled */

	readl_poll_timeout(prg->regs + IPU_PRG_STATUS, val,

			   (val & IPU_PRG_STATUS_BUFFER0_READY(prg_chan)) &&

			   (val & IPU_PRG_STATUS_BUFFER1_READY(prg_chan)),

			   5, 1000);



	clk_disable_unprepare(prg->clk_ipg);



	chan->enabled = true;