[igt-dev] [PATCH i-g-t 1/2] igt_eld: Add eld_is_igt

Arkadiusz Hiler
2019-09-20T10:47:44Z

From: Simon Ser <simon.ser@intel.com>

This function parses the monitor name from an ELD blob and checks whether it
comes from an IGT EDID.

v2: replace a bunch of random numbers with constants (Chris, Andi)
v3: rabase and fix subject (Arek)

Signed-off-by: Simon Ser <simon.ser@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Martin Peres <martin.peres@linux.intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
---
lib/igt_eld.c | 29 +++++++++++++++++++++++++++++
lib/igt_eld.h | 1 +
2 files changed, 30 insertions(+)

diff --git a/lib/igt_eld.c b/lib/igt_eld.c
index 23ebf630..ef6625df 100644
--- a/lib/igt_eld.c
+++ b/lib/igt_eld.c
@@ -283,3 +283,32 @@ bool eld_is_supported(void)

return has_elds;
}
+
+#define ELD_MAX_SIZE 256
+#define MONITOR_NAME_OFFSET 20
+#define MONITOR_NAME_MAX_SIZE 16
+
+/** eld_is_igt: check whether the ELD blob comes from an IGT EDID */
+bool eld_is_igt(const char *eld, size_t eld_size)
+{
+ char name[MONITOR_NAME_MAX_SIZE + 1];
+ int name_size;
+
+ igt_assert_f(eld_size >= MONITOR_NAME_OFFSET &&
+ eld_size <= ELD_MAX_SIZE,
+ "Invalid ELD size: %zu\n", eld_size);
+
+ name_size = eld[4] & 0x1F;
+ igt_assert_f(name_size <= MONITOR_NAME_MAX_SIZE &&
+ MONITOR_NAME_OFFSET + name_size <= eld_size,
+ "Invalid monitor name size in ELD: %d\n", name_size);
+ if (name_size == 0) {
+ igt_debug("ELD doesn't contain a monitor name\n");
+ return false;
+ }
+
+ memcpy(name, &eld[MONITOR_NAME_OFFSET], name_size);
+ name[name_size] = '\0';
+ igt_debug("Checking ELD with monitor name: %s\n", name);
+ return strcmp(name, "IGT") == 0;
+}
diff --git a/lib/igt_eld.h b/lib/igt_eld.h
index 4b917a62..30d7012d 100644
--- a/lib/igt_eld.h
+++ b/lib/igt_eld.h
@@ -52,5 +52,6 @@ struct eld_entry {
bool eld_is_supported(void);
bool eld_get_igt(struct eld_entry *eld);
bool eld_has_igt(void);
+bool eld_is_igt(const char *eld, size_t eld_size);

#endif
--
2.21.0