diff mbox series

[v6,2/2] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory region as reserved

Message ID 20230726132719.2117369-2-amit.pundir@linaro.org
State Accepted
Commit 110e70fccce4f22b53986ae797d665ffb1950aa6
Headers show
Series [v6,1/2] dt-bindings: display/msm: mdss-common: add memory-region property | expand

Commit Message

Amit Pundir July 26, 2023, 1:27 p.m. UTC 
Adding a reserved memory region for the framebuffer memory
(the splash memory region set up by the bootloader).

It fixes a kernel panic (arm-smmu: Unhandled context fault
at this particular memory region) reported on DB845c running
v5.10.y.

Cc: stable@vger.kernel.org # v5.10+
Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
v6: Collected review tag, updated commit message for the
    context and marked for stable kernel versions.

v5: Re-sending with updated dt-bindings patch in mdss-common
    schema.

v4: Re-sending this along with a new dt-bindings patch to
    document memory-region property in qcom,sdm845-mdss
    schema and keep dtbs_check happy.

v3: Point this reserved region to MDSS.

v2: Updated commit message.

There was some dicussion on v1 but it didn't go anywhere,
https://lore.kernel.org/linux-kernel/20230124182857.1524912-1-amit.pundir@linaro.org/T/#u.
The general consensus is that this memory should be freed and be
made resuable but that (releasing this piece of memory) has been
tried before and it is not trivial to return the reserved memory
node to the system RAM pool in this case.

 arch/arm64/boot/dts/qcom/sdm845-db845c.dts | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
index d6b464cb61d6..f546f6f57c1e 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
@@ -101,6 +101,14 @@  hdmi_con: endpoint {
 		};
 	};
 
+	reserved-memory {
+		/* Cont splash region set up by the bootloader */
+		cont_splash_mem: framebuffer@9d400000 {
+			reg = <0x0 0x9d400000 0x0 0x2400000>;
+			no-map;
+		};
+	};
+
 	lt9611_1v8: lt9611-vdd18-regulator {
 		compatible = "regulator-fixed";
 		regulator-name = "LT9611_1V8";
@@ -506,6 +514,7 @@  &i2c14 {
 };
 
 &mdss {
+	memory-region = <&cont_splash_mem>;
 	status = "okay";
 };