From 0faf9dc4a41a8babec565ea0b3df6e7b4cd01ea1 Mon Sep 17 00:00:00 2001
From: Frank Praznik <[EMAIL REDACTED]>
Date: Fri, 18 Oct 2024 11:25:10 -0400
Subject: [PATCH] kmsdrm: Support sorting displays via the priority hint
Use the connector name for displays and sort them according to priority, if the hint is set.
---
include/SDL3/SDL_hints.h | 5 ++-
src/video/kmsdrm/SDL_kmsdrmsym.h | 2 +
src/video/kmsdrm/SDL_kmsdrmvideo.c | 60 ++++++++++++++++++++++++++++++
3 files changed, 65 insertions(+), 2 deletions(-)
diff --git a/include/SDL3/SDL_hints.h b/include/SDL3/SDL_hints.h
index 33baa75c73f89..3afd1a5676344 100644
--- a/include/SDL3/SDL_hints.h
+++ b/include/SDL3/SDL_hints.h
@@ -3149,13 +3149,14 @@ extern "C" {
* prioritized in the list of displays, as exposed by calling
* SDL_GetDisplays(), with the first listed becoming the primary display. The
* naming convention can vary depending on the environment, but it is usually
- * a connector name (e.g. 'DP-1', 'DP-2', 'HDMI-1', etc...).
+ * a connector name (e.g. 'DP-1', 'DP-2', 'HDMI-A-1',etc...).
*
- * On X11 and Wayland desktops, the connector names associated with displays
+ * On Wayland and X11 desktops, the connector names associated with displays
* can typically be found by using the `xrandr` utility.
*
* This hint is currently supported on the following drivers:
*
+ * - KMSDRM (kmsdrm)
* - Wayland (wayland)
*
* This hint should be set before SDL is initialized.
diff --git a/src/video/kmsdrm/SDL_kmsdrmsym.h b/src/video/kmsdrm/SDL_kmsdrmsym.h
index 1f0646636ebcd..5f389d854ab2f 100644
--- a/src/video/kmsdrm/SDL_kmsdrmsym.h
+++ b/src/video/kmsdrm/SDL_kmsdrmsym.h
@@ -63,6 +63,8 @@ SDL_KMSDRM_SYM_OPT(int,drmModeAddFB2WithModifiers,(int fd, uint32_t width,
const uint32_t pitches[4], const uint32_t offsets[4],
const uint64_t modifier[4], uint32_t *buf_id, uint32_t flags))
+SDL_KMSDRM_SYM_OPT(const char *,drmModeGetConnectorTypeName,(uint32_t connector_type))
+
SDL_KMSDRM_SYM(int,drmModeRmFB,(int fd, uint32_t bufferId))
SDL_KMSDRM_SYM(drmModeFBPtr,drmModeGetFB,(int fd, uint32_t buf))
SDL_KMSDRM_SYM(drmModeCrtcPtr,drmModeGetCrtc,(int fd, uint32_t crtcId))
diff --git a/src/video/kmsdrm/SDL_kmsdrmvideo.c b/src/video/kmsdrm/SDL_kmsdrmvideo.c
index 9097254ad7657..ae9b623583ccd 100644
--- a/src/video/kmsdrm/SDL_kmsdrmvideo.c
+++ b/src/video/kmsdrm/SDL_kmsdrmvideo.c
@@ -799,8 +799,10 @@ static void KMSDRM_AddDisplay(SDL_VideoDevice *_this, drmModeConnector *connecto
SDL_DisplayModeData *modedata = NULL;
drmModeEncoder *encoder = NULL;
drmModeCrtc *crtc = NULL;
+ const char *connector_type = NULL;
SDL_DisplayID display_id;
SDL_PropertiesID display_properties;
+ char name_fmt[64];
int orientation;
int mode_index;
int i, j;
@@ -963,6 +965,15 @@ static void KMSDRM_AddDisplay(SDL_VideoDevice *_this, drmModeConnector *connecto
KMSDRM_CrtcSetVrr(viddata->drm_fd, crtc->crtc_id, true);
}
+ // Set the name by the connector type, if possible
+ if (KMSDRM_drmModeGetConnectorTypeName) {
+ connector_type = KMSDRM_drmModeGetConnectorTypeName(connector->connector_type);
+ if (connector_type == NULL) {
+ connector_type = "Unknown";
+ }
+ SDL_snprintf(name_fmt, sizeof(name_fmt), "%s-%u", connector_type, connector->connector_type_id);
+ }
+
/*****************************************/
// Part 2: setup the SDL_Display itself.
/*****************************************/
@@ -984,6 +995,9 @@ static void KMSDRM_AddDisplay(SDL_VideoDevice *_this, drmModeConnector *connecto
CalculateRefreshRate(&dispdata->mode, &display.desktop_mode.refresh_rate_numerator, &display.desktop_mode.refresh_rate_denominator);
display.desktop_mode.format = SDL_PIXELFORMAT_ARGB8888;
display.desktop_mode.internal = modedata;
+ if (connector_type) {
+ display.name = name_fmt;
+ }
// Add the display to the list of SDL displays.
display_id = SDL_AddVideoDisplay(&display, false);
@@ -1016,6 +1030,49 @@ static void KMSDRM_AddDisplay(SDL_VideoDevice *_this, drmModeConnector *connecto
}
} // NOLINT(clang-analyzer-unix.Malloc): If no error `dispdata` is saved in the display
+static void KMSDRM_SortDisplays(SDL_VideoDevice *_this)
+{
+ const char *name_hint = SDL_GetHint(SDL_HINT_VIDEO_DISPLAY_PRIORITY);
+
+ if (name_hint) {
+ char *saveptr;
+ char *str = SDL_strdup(name_hint);
+ SDL_VideoDisplay **sorted_list = SDL_malloc(sizeof(SDL_VideoDisplay *) * _this->num_displays);
+
+ if (str && sorted_list) {
+ int sorted_index = 0;
+
+ // Sort the requested displays to the front of the list.
+ const char *token = SDL_strtok_r(str, ",", &saveptr);
+ while (token) {
+ for (int i = 0; i < _this->num_displays; ++i) {
+ SDL_VideoDisplay *d = _this->displays[i];
+ if (d && SDL_strcmp(token, d->name) == 0) {
+ sorted_list[sorted_index++] = d;
+ _this->displays[i] = NULL;
+ break;
+ }
+ }
+
+ token = SDL_strtok_r(NULL, ",", &saveptr);
+ }
+
+ // Append the remaining displays to the end of the list.
+ for (int i = 0; i < _this->num_displays; ++i) {
+ if (_this->displays[i]) {
+ sorted_list[sorted_index++] = _this->displays[i];
+ }
+ }
+
+ // Copy the sorted list back to the display list.
+ SDL_memcpy(_this->displays, sorted_list, sizeof(SDL_VideoDisplay *) * _this->num_displays);
+ }
+
+ SDL_free(str);
+ SDL_free(sorted_list);
+ }
+}
+
/* Initializes the list of SDL displays: we build a new display for each
connecter connector we find.
This is to be called early, in VideoInit(), because it gets us
@@ -1078,6 +1135,9 @@ static bool KMSDRM_InitDisplays(SDL_VideoDevice *_this)
goto cleanup;
}
+ // Sort the displays, if necessary
+ KMSDRM_SortDisplays(_this);
+
// Determine if video hardware supports async pageflips.
if (KMSDRM_drmGetCap(viddata->drm_fd, DRM_CAP_ASYNC_PAGE_FLIP, &async_pageflip) != 0) {
SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not determine async page flip capability.");