1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
From dfa14cd3f9f46c53d477a5d7410af52f400e0e90 Mon Sep 17 00:00:00 2001
From: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Date: Wed, 10 May 2017 18:24:24 -0400
Subject: [PATCH 0426/4131] drm/amd/display: add explanation for
surface_update_type
Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
drivers/gpu/drm/amd/display/dc/dc.h | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index 7dd145b..9a19d6f 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -434,9 +434,35 @@ bool dc_post_update_surfaces_to_stream(
void dc_update_surfaces_for_stream(struct dc *dc, struct dc_surface_update *updates,
int surface_count, const struct dc_stream *stream);
+/* Surface update type is used by dc_update_surfaces_and_stream
+ * The update type is determined at the very beginning of the function based
+ * on parameters passed in and decides how much programming (or updating) is
+ * going to be done during the call.
+ *
+ * UPDATE_TYPE_FAST is used for really fast updates that do not require much
+ * logical calculations or hardware register programming. This update MUST be
+ * ISR safe on windows. Currently fast update will only be used to flip surface
+ * address.
+ *
+ * UPDATE_TYPE_MED is used for slower updates which require significant hw
+ * re-programming however do not affect bandwidth consumption or clock
+ * requirements. At present, this is the level at which front end updates
+ * that do not require us to run bw_calcs happen. These are in/out transfer func
+ * updates, viewport offset changes, recout size changes and pixel depth changes.
+ * This update can be done at ISR, but we want to minimize how often this happens.
+ *
+ * UPDATE_TYPE_FULL is slow. Really slow. This requires us to recalculate our
+ * bandwidth and clocks, possibly rearrange some pipes and reprogram anything front
+ * end related. Any time viewport dimensions, recout dimensions, scaling ratios or
+ * gamma need to be adjusted or pipe needs to be turned on (or disconnected) we do
+ * a full update. This cannot be done at ISR level and should be a rare event.
+ * Unless someone is stress testing mpo enter/exit, playing with colour or adjusting
+ * underscan we don't expect to see this call at all.
+ */
+
enum surface_update_type {
UPDATE_TYPE_FAST, /* super fast, safe to execute in isr */
- UPDATE_TYPE_MED, /* a lot of programming needed. may need to alloc */
+ UPDATE_TYPE_MED, /* ISR safe, most of programming needed, no bw/clk change*/
UPDATE_TYPE_FULL, /* may need to shuffle resources */
};
--
2.7.4
|
