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Fix libdrm return value vs errno confusion

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libdrm is inconsistent between returning -1 with an errno set
and just returning -errno as the return value. Figuring out which
behavior a given libdrm function has require reading the source :/
This commit is contained in:
Cameron Gutman 2026-01-04 21:46:49 -06:00
commit bd32370b6d
2 changed files with 39 additions and 30 deletions
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6
app/streaming/video/ffmpeg-renderers/drm.cpp
View file

@ -827,7 +827,7 @@ void DrmRenderer::setHdrMode(bool enabled)
m_HdrOutputMetadataBlobId = 0; m_HdrOutputMetadataBlobId = 0;
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"drmModeCreatePropertyBlob() failed: %d", "drmModeCreatePropertyBlob() failed: %d",
errno); err);
// Non-fatal // Non-fatal
} }
} }
@ -1083,7 +1083,7 @@ bool DrmRenderer::uploadSurfaceToFb(SDL_Surface *surface, uint32_t* handle, uint
if (err < 0) { if (err < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"drmModeAddFB2() failed: %d", "drmModeAddFB2() failed: %d",
errno); err);
goto Fail; goto Fail;
} }
@ -1312,7 +1312,7 @@ bool DrmRenderer::addFbForFrame(AVFrame *frame, uint32_t* newFbId, bool testMode
if (err < 0) { if (err < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"drmModeAddFB2[WithModifiers]() failed: %d", "drmModeAddFB2[WithModifiers]() failed: %d",
errno); err);
return false; return false;
} }

63
app/streaming/video/ffmpeg-renderers/drm.h
View file

@ -262,7 +262,7 @@ class DrmRenderer : public IFFmpegRenderer {
} }
bool set(const DrmProperty& prop, uint64_t value, bool verbose = true) { bool set(const DrmProperty& prop, uint64_t value, bool verbose = true) {
bool ret; int err;
if (m_Atomic) { if (m_Atomic) {
// Synchronize with other threads that might be committing or setting properties // Synchronize with other threads that might be committing or setting properties
@ -272,26 +272,32 @@ class DrmRenderer : public IFFmpegRenderer {
m_AtomicReq = drmModeAtomicAlloc(); m_AtomicReq = drmModeAtomicAlloc();
} }
ret = drmModeAtomicAddProperty(m_AtomicReq, prop.objectId(), prop.id(), value) > 0; err = drmModeAtomicAddProperty(m_AtomicReq, prop.objectId(), prop.id(), value);
// This returns the new count of properties on success,
// so normalize it to 0 like drmModeObjectSetProperty()
if (err > 0) {
err = 0;
}
} }
else { else {
ret = drmModeObjectSetProperty(m_Fd, prop.objectId(), prop.objectType(), prop.id(), value) == 0; err = drmModeObjectSetProperty(m_Fd, prop.objectId(), prop.objectType(), prop.id(), value);
} }
if (verbose && ret) { if (verbose && err == 0) {
SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION, SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION,
"Set property '%s': %" PRIu64, "Set property '%s': %" PRIu64,
prop.name(), prop.name(),
value); value);
} }
else if (!ret) { else if (err < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"Failed to set property '%s': %d", "Failed to set property '%s': %d",
prop.name(), prop.name(),
errno); err);
} }
return ret; return err == 0;
} }
bool set(const DrmProperty& prop, const std::string &value) { bool set(const DrmProperty& prop, const std::string &value) {
@ -349,27 +355,30 @@ class DrmRenderer : public IFFmpegRenderer {
planeConfig = m_PlaneConfigs.at(plane.objectId()); planeConfig = m_PlaneConfigs.at(plane.objectId());
} }
ret = drmModeSetPlane(m_Fd, plane.objectId(), int err = drmModeSetPlane(m_Fd, plane.objectId(),
planeConfig.crtcId, fbId, 0, planeConfig.crtcId, fbId, 0,
planeConfig.crtcX, planeConfig.crtcY, planeConfig.crtcX, planeConfig.crtcY,
planeConfig.crtcW, planeConfig.crtcH, planeConfig.crtcW, planeConfig.crtcH,
planeConfig.srcX, planeConfig.srcY, planeConfig.srcX, planeConfig.srcY,
planeConfig.srcW, planeConfig.srcH) == 0; planeConfig.srcW, planeConfig.srcH);
// If we succeeded updating the plane, free the old FB state // If we succeeded updating the plane, free the old FB state
// Otherwise, we'll free the new data which was never used. // Otherwise, we'll free the new data which was never used.
if (ret) { if (err == 0) {
std::lock_guard lg { m_Lock }; std::lock_guard lg { m_Lock };
auto &pb = m_PlaneBuffers[plane.objectId()]; auto &pb = m_PlaneBuffers[plane.objectId()];
std::swap(fbId, pb.fbId); std::swap(fbId, pb.fbId);
std::swap(dumbBufferHandle, pb.dumbBufferHandle); std::swap(dumbBufferHandle, pb.dumbBufferHandle);
std::swap(frame, pb.frame); std::swap(frame, pb.frame);
ret = true;
} }
else { else {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"drmModeSetPlane() failed: %d", "drmModeSetPlane() failed: %d",
errno); err);
ret = false;
} }
} }
@ -452,27 +461,27 @@ class DrmRenderer : public IFFmpegRenderer {
} }
// Try an async flip if requested // Try an async flip if requested
bool ret = drmModeAtomicCommit(m_Fd, m_AtomicReq, int err = drmModeAtomicCommit(m_Fd, m_AtomicReq,
m_AsyncFlip ? DRM_MODE_PAGE_FLIP_ASYNC : DRM_MODE_ATOMIC_ALLOW_MODESET, m_AsyncFlip ? DRM_MODE_PAGE_FLIP_ASYNC : DRM_MODE_ATOMIC_ALLOW_MODESET,
nullptr) == 0; nullptr);
// The driver may not support async flips (especially if we changed a non-FB_ID property), // The driver may not support async flips (especially if we changed a non-FB_ID property),
// so try again with a regular flip if we get an error from the async flip attempt. // so try again with a regular flip if we get an error from the async flip attempt.
// //
// We pass DRM_MODE_ATOMIC_ALLOW_MODESET because changing HDR state may require a modeset. // We pass DRM_MODE_ATOMIC_ALLOW_MODESET because changing HDR state may require a modeset.
if (!ret && m_AsyncFlip) { if (err < 0 && m_AsyncFlip) {
ret = drmModeAtomicCommit(m_Fd, m_AtomicReq, DRM_MODE_ATOMIC_ALLOW_MODESET, this) == 0; err = drmModeAtomicCommit(m_Fd, m_AtomicReq, DRM_MODE_ATOMIC_ALLOW_MODESET, this);
} }
if (!ret) { if (err < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"drmModeAtomicCommit() failed: %d", "drmModeAtomicCommit() failed: %d",
errno); err);
} }
// Update the buffer state for any modified planes // Update the buffer state for any modified planes
std::lock_guard lg { m_Lock }; std::lock_guard lg { m_Lock };
for (auto it = pendingBuffers.begin(); it != pendingBuffers.end(); it++) { for (auto it = pendingBuffers.begin(); it != pendingBuffers.end(); it++) {
if (ret && it->second.modified) { if (err == 0 && it->second.modified) {
if (it->second.fbId) { if (it->second.fbId) {
drmModeRmFB(m_Fd, it->second.fbId); drmModeRmFB(m_Fd, it->second.fbId);
it->second.fbId = 0; it->second.fbId = 0;
@ -491,14 +500,14 @@ class DrmRenderer : public IFFmpegRenderer {
pb.dumbBufferHandle = it->second.pendingDumbBuffer; pb.dumbBufferHandle = it->second.pendingDumbBuffer;
pb.frame = it->second.pendingFrame; pb.frame = it->second.pendingFrame;
} }
else if (!ret || it->second.fbId || it->second.dumbBufferHandle || it->second.frame) { else if (err < 0 || it->second.fbId || it->second.dumbBufferHandle || it->second.frame) {
// Free the old pending buffers on a failed commit // Free the old pending buffers on a failed commit
if (it->second.pendingFbId) { if (it->second.pendingFbId) {
SDL_assert(!ret); SDL_assert(err < 0);
drmModeRmFB(m_Fd, it->second.pendingFbId); drmModeRmFB(m_Fd, it->second.pendingFbId);
} }
if (it->second.pendingDumbBuffer) { if (it->second.pendingDumbBuffer) {
SDL_assert(!ret); SDL_assert(err < 0);
struct drm_mode_destroy_dumb destroyBuf = {}; struct drm_mode_destroy_dumb destroyBuf = {};
destroyBuf.handle = it->second.pendingDumbBuffer; destroyBuf.handle = it->second.pendingDumbBuffer;
drmIoctl(m_Fd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroyBuf); drmIoctl(m_Fd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroyBuf);
@ -518,7 +527,7 @@ class DrmRenderer : public IFFmpegRenderer {
} }
drmModeAtomicFree(req); drmModeAtomicFree(req);
return ret; return err == 0;
} }
bool isAtomic() { bool isAtomic() {