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/**
* @file mce-fbdev.c
* Frame buffer device handling code for the Mode Control Entity
* <p>
* Copyright 2015 Jolla Ltd.
* <p>
* @author Simo Piiroinen <simo.piiroinen@jollamobile.com>
*
* mce is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License
* version 2.1 as published by the Free Software Foundation.
*
* mce is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mce. If not, see <http://www.gnu.org/licenses/>.
*/
#include "mce-fbdev.h"
#include "mce-log.h"
#include "mce.h"
#ifdef ENABLE_HYBRIS
# include "mce-hybris.h"
#endif
#include <linux/fb.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
/* ========================================================================= *
* CONSTANTS
* ========================================================================= */
/** Path to the framebuffer device */
#define FB_DEVICE "/dev/fb0"
/* ========================================================================= *
* STATE_DATA
* ========================================================================= */
/** File descriptor for frame buffer device */
static int mce_fbdev_handle = -1;
/** Flag for: use hybris for fb power control */
#ifdef ENABLE_HYBRIS
static bool fbdev_use_hybris = false;
#endif
/** Flag for: Opening frame buffer device is allowed */
static bool mce_fbdev_allow_open = false;
/* ========================================================================= *
* FBDEV_FILE_DESCRIPTOR
* ========================================================================= */
/** Frame buffer is open predicate
*
* @return true if frame buffer device is currently opened, false otherwise
*/
bool mce_fbdev_is_open(void)
{
return mce_fbdev_handle != -1;
}
/** Open frame buffer device unless denied
*
* @return true on success, or false on failure
*/
bool mce_fbdev_open(void)
{
#ifdef ENABLE_HYBRIS
if( fbdev_use_hybris )
goto EXIT;
#endif
if( mce_fbdev_handle != -1 )
goto EXIT;
if( !mce_fbdev_allow_open )
goto EXIT;
mce_log(LL_NOTICE, "open frame buffer device");
if( (mce_fbdev_handle = open(FB_DEVICE, O_RDWR)) == -1 ) {
if( errno != ENOENT )
mce_log(LL_WARN, "failed to open frame buffer device: %m");
goto EXIT;
}
mce_log(LL_DEBUG, "frame buffer device opened");
EXIT:
return mce_fbdev_handle != -1;
}
/** Close frame buffer device
*/
void mce_fbdev_close(void)
{
if( mce_fbdev_handle == -1 )
goto EXIT;
mce_log(LL_NOTICE, "closing frame buffer device");
close(mce_fbdev_handle), mce_fbdev_handle = -1;
mce_log(LL_DEBUG, "closed frame buffer device");
EXIT:
return;
}
/** Reopen frame buffer device unless denied
*/
void mce_fbdev_reopen(void)
{
if( mce_fbdev_allow_open )
mce_fbdev_close();
mce_fbdev_open();
}
/* ========================================================================= *
* POST_EXIT_LINGER
* ========================================================================= */
/** Signal handler that just exits
*
* @param sig signal number (unused)
*/
static void mce_fbdev_linger_signal_hander(int sig)
{
(void) sig;
_exit(EXIT_SUCCESS);
}
/** Create a child process to keep frame buffer device open after mce exits
*
* The frame buffer device powers off automatically when the last open
* file descriptor gets closed.
*
* To allow the shutdown logo to stay on screen after lipstick and mce
* have been terminated, we create a detached child process that hangs
* on to frame buffer device.
*
* @param delay_ms how long the child process should linger
*/
void mce_fbdev_linger_after_exit(int delay_ms)
{
static const char msg[] = "closing frame buffer device after delay\n";
/* Fork a child process */
int child_pid = fork();
/* Deal with parent side and return to caller */
if( child_pid != 0 ) {
if( child_pid < 0 )
mce_log(LL_ERR, "forking fbdev linger child failed: %m");
else
mce_log(LL_DEBUG, "fbdev linger child: pid %d", child_pid);
return;
}
/* Detach from parent so that we will not get killed with it */
setsid();
/* The parent process needs to pay special attention to signals
* in order not to leave wakelocks active on exit. Also some
* signals are transferred to mainloop via a pipe. None of this
* should happen if the child process gets signals -> remove
* all signal handlers the parent process has installed. */
mce_signal_handlers_remove();
/* Since the intent is that the child process exits very close to
* power off, it is unlikely that core can be succesfully dumped
* and processed -> trap all signals that do core dump by default
* and make an _exit() instead. */
static const int trap[] =
{
SIGQUIT, SIGILL, SIGABRT, SIGFPE, SIGSEGV,
SIGBUS, SIGSYS, SIGTRAP, SIGXCPU, SIGXFSZ,
-1
};
for( size_t i = 0; trap[i] != -1; ++i )
signal(trap[i], mce_fbdev_linger_signal_hander);
/* Close all files, except fbdev & stderr */
int nfd = getdtablesize();
for( int fd = 0; fd < nfd; ++fd ) {
if( fd != mce_fbdev_handle && fd != STDERR_FILENO )
close(fd);
}
if( delay_ms < 500 )
delay_ms = 500;
/* Wait ... */
struct timespec ts =
{
.tv_sec = (time_t)(delay_ms / 1000),
.tv_nsec = (long)(delay_ms % 1000) * 1000000,
};
while( nanosleep(&ts, &ts) == -1 && errno == EINTR ) { /* nop */ }
/* If journald is still up, the end-of-linger message written to stderr
* ends up in journal and attributed to parent mce process.
*
* ... and in case journald has already made an exit, we do not want
* to die by SIGPIPE, so it needs to be ignored. */
signal(SIGPIPE, SIG_IGN);
if( write(STDERR_FILENO, msg, sizeof msg - 1) < 0 ) { /* dontcare */ }
/* Exit - the frame buffer device will power off if we
* were the last process to have an open file descriptor */
_exit(EXIT_SUCCESS);
}
/* ========================================================================= *
* FRAMEBUFFER_POWER
* ========================================================================= */
/** Set the frame buffer power state
*
* MCE uses this function for display power control only if autosuspend
* control sysfs files are not present.
*
* If there is a hw composer that is also doing fbdev ioctl() calls,
* there is some change that kernel side troubles can be caused by
* having two entities trying to control the same resource.
*
* @param power_in true to power up, false to power down
*/
void mce_fbdev_set_power(bool power_on)
{
mce_log(LL_DEBUG, "fbdev power %s", power_on ? "up" : "down");
if( mce_fbdev_handle != -1 ) {
int value = power_on ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
if( ioctl(mce_fbdev_handle, FBIOBLANK, value) == -1 )
mce_log(LL_ERR, "%s: ioctl(FBIOBLANK,%d): %m", FB_DEVICE, value);
else
mce_log(LL_DEBUG, "success");
}
#ifdef ENABLE_HYBRIS
else if( fbdev_use_hybris ) {
mce_hybris_framebuffer_set_power(power_on);
}
#endif
return;
}
/* ========================================================================= *
* MODULE_INIT
* ========================================================================= */
/** Initialize frame buffer module
*/
void mce_fbdev_init(void)
{
/* allow opening frame buffer device */
mce_fbdev_allow_open = true;
if( mce_fbdev_open() ) {
mce_log(LL_NOTICE, "using ioctl for fb power control");
}
#ifdef ENABLE_HYBRIS
else if( mce_hybris_framebuffer_init() ) {
mce_log(LL_NOTICE, "using libhybris for fb power control");
fbdev_use_hybris = true;
}
#endif
else {
mce_log(LL_WARN, "no fb power control available");;
}
}
/** De-initialize frame buffer module
*/
void mce_fbdev_quit(void)
{
/* deny opening frame buffer device */
mce_fbdev_allow_open = false;
mce_fbdev_close();
#ifdef ENABLE_HYBRIS
if( fbdev_use_hybris ) {
fbdev_use_hybris = false;
mce_hybris_framebuffer_quit();
}
#endif
}