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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chromeos/display/output_util.h"
#include <X11/extensions/Xrandr.h>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
#include "base/strings/string_util.h"
#include "base/x11/edid_parser_x11.h"
namespace chromeos {
namespace {
// Prefixes for the built-in displays.
const char kInternal_LVDS[] = "LVDS";
const char kInternal_eDP[] = "eDP";
const char kInternal_DSI[] = "DSI";
// Gets some useful data from the specified output device, such like
// manufacturer's ID, product code, and human readable name. Returns false if it
// fails to get those data and doesn't touch manufacturer ID/product code/name.
// NULL can be passed for unwanted output parameters.
bool GetOutputDeviceData(XID output,
uint16* manufacturer_id,
std::string* human_readable_name) {
unsigned long nitems = 0;
unsigned char *prop = NULL;
if (!base::GetEDIDProperty(output, &nitems, &prop))
return false;
bool result = base::ParseOutputDeviceData(
prop, nitems, manufacturer_id, human_readable_name);
XFree(prop);
return result;
}
} // namespace
std::string GetDisplayName(XID output_id) {
std::string display_name;
GetOutputDeviceData(output_id, NULL, &display_name);
return display_name;
}
bool GetOutputOverscanFlag(XID output, bool* flag) {
unsigned long nitems = 0;
unsigned char *prop = NULL;
if (!base::GetEDIDProperty(output, &nitems, &prop))
return false;
bool found = ParseOutputOverscanFlag(prop, nitems, flag);
XFree(prop);
return found;
}
bool ParseOutputOverscanFlag(const unsigned char* prop,
unsigned long nitems,
bool *flag) {
// See http://en.wikipedia.org/wiki/Extended_display_identification_data
// for the extension format of EDID. Also see EIA/CEA-861 spec for
// the format of the extensions and how video capability is encoded.
// - byte 0: tag. should be 02h.
// - byte 1: revision. only cares revision 3 (03h).
// - byte 4-: data block.
const unsigned int kExtensionBase = 128;
const unsigned int kExtensionSize = 128;
const unsigned int kNumExtensionsOffset = 126;
const unsigned int kDataBlockOffset = 4;
const unsigned char kCEAExtensionTag = '\x02';
const unsigned char kExpectedExtensionRevision = '\x03';
const unsigned char kExtendedTag = 7;
const unsigned char kExtendedVideoCapabilityTag = 0;
const unsigned int kPTOverscan = 4;
const unsigned int kITOverscan = 2;
const unsigned int kCEOverscan = 0;
if (nitems <= kNumExtensionsOffset)
return false;
unsigned char num_extensions = prop[kNumExtensionsOffset];
for (size_t i = 0; i < num_extensions; ++i) {
// Skip parsing the whole extension if size is not enough.
if (nitems < kExtensionBase + (i + 1) * kExtensionSize)
break;
const unsigned char* extension = prop + kExtensionBase + i * kExtensionSize;
unsigned char tag = extension[0];
unsigned char revision = extension[1];
if (tag != kCEAExtensionTag || revision != kExpectedExtensionRevision)
continue;
unsigned char timing_descriptors_start =
std::min(extension[2], static_cast<unsigned char>(kExtensionSize));
const unsigned char* data_block = extension + kDataBlockOffset;
while (data_block < extension + timing_descriptors_start) {
// A data block is encoded as:
// - byte 1 high 3 bits: tag. '07' for extended tags.
// - byte 1 remaining bits: the length of data block.
// - byte 2: the extended tag. '0' for video capability.
// - byte 3: the capability.
unsigned char tag = data_block[0] >> 5;
unsigned char payload_length = data_block[0] & 0x1f;
if (static_cast<unsigned long>(data_block + payload_length - prop) >
nitems)
break;
if (tag != kExtendedTag || payload_length < 2) {
data_block += payload_length + 1;
continue;
}
unsigned char extended_tag_code = data_block[1];
if (extended_tag_code != kExtendedVideoCapabilityTag) {
data_block += payload_length + 1;
continue;
}
// The difference between preferred, IT, and CE video formats
// doesn't matter. Sets |flag| to true if any of these flags are true.
if ((data_block[2] & (1 << kPTOverscan)) ||
(data_block[2] & (1 << kITOverscan)) ||
(data_block[2] & (1 << kCEOverscan))) {
*flag = true;
} else {
*flag = false;
}
return true;
}
}
return false;
}
bool IsInternalOutputName(const std::string& name) {
return name.find(kInternal_LVDS) == 0 || name.find(kInternal_eDP) == 0 ||
name.find(kInternal_DSI) == 0;
}
const XRRModeInfo* FindXRRModeInfo(const XRRScreenResources* screen_resources,
XID current_mode) {
for (int m = 0; m < screen_resources->nmode; m++) {
XRRModeInfo *mode = &screen_resources->modes[m];
if (mode->id == current_mode)
return mode;
}
return NULL;
}
namespace test {
XRRModeInfo CreateModeInfo(int id,
int width,
int height,
bool interlaced,
float refresh_rate) {
XRRModeInfo mode_info = {0};
mode_info.id = id;
mode_info.width = width;
mode_info.height = height;
if (interlaced)
mode_info.modeFlags = RR_Interlace;
if (refresh_rate != 0.0f) {
mode_info.hTotal = 1;
mode_info.vTotal = 1;
mode_info.dotClock = refresh_rate;
}
return mode_info;
}
} // namespace test
} // namespace chromeos
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