Thread (16 messages) read the whole thread 16 messages, 4 authors, 2023-06-27

Re: [PATCH V5 5/6] coresight: platform: acpi: Ignore the absence of graph

From: Mike Leach <hidden>
Date: 2023-06-07 09:01:31
Also in: linux-acpi, linux-devicetree, lkml

HI Ansuman,

On Mon, 29 May 2023 at 07:26, Anshuman Khandual
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Suzuki K Poulose <suzuki.poulose@arm.com>

Some components may not have graph connections for describing
the trace path. e.g., ETE, where it could directly use the per
CPU TRBE. Ignore the absence of graph connections

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <redacted>
---
 drivers/hwtracing/coresight/coresight-platform.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 475899714104..c4b4fbde8550 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -692,8 +692,12 @@ static int acpi_coresight_parse_graph(struct acpi_device *adev,

        pdata->nr_inport = pdata->nr_outport = 0;
        graph = acpi_get_coresight_graph(adev);
+       /*
+        * There are no graph connections, which is fine for some components.
+        * e.g., ETE
+        */
        if (!graph)
-               return -ENOENT;
+               return 0;
Should we not determine if it is valid for a particular component not
to have a graph connection?
Prior to this patch an incorrectly configured ETMv4 - which must have
a graph would return an error, after this it will fail silently

Mike
        nlinks = graph->package.elements[2].integer.value;
        if (!nlinks)
--
2.25.1

-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

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