[PATCH V2] drm/exynos: enable fimd clocks in probe before accessing fimd registers

Rahul Sharma rahul.sharma at samsung.com
Wed May 21 22:16:07 PDT 2014

From: Rahul Sharma <Rahul.Sharma at samsung.com>

Fimd probe is accessing fimd Registers without enabling the fimd
gate clocks. If FIMD clocks are kept disabled in Uboot or disbaled
during kernel boottime, the system hangs during boottime.

This issue got surfaced when verifying with sysmmu enabled. Probe of
fimd Sysmmu enables the master clock before accessing sysmmu regs and
then disables. Later fimd probe tries to read the register without
enabling the clock which is wrong and hangs the system.

Signed-off-by: Rahul Sharma <Rahul.Sharma at samsung.com>
Rebased on exynos-drm-next branch.

 drivers/gpu/drm/exynos/exynos_drm_fimd.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 173ee97..a79ba0a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -891,9 +891,15 @@ static int fimd_bind(struct device *dev, struct device *master, void *data)
 	if (ctx->display)
 		exynos_drm_create_enc_conn(drm_dev, ctx->display);
+	clk_prepare_enable(ctx->bus_clk);
+	clk_prepare_enable(ctx->lcd_clk);
 	for (win = 0; win < WINDOWS_NR; win++)
 		fimd_clear_win(ctx, win);
+	clk_disable_unprepare(ctx->lcd_clk);
+	clk_disable_unprepare(ctx->bus_clk);
 	return 0;

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