Index: libs/libmythtv/osdtypeteletext.cpp =================================================================== --- libs/libmythtv/osdtypeteletext.cpp (revision 13437) +++ libs/libmythtv/osdtypeteletext.cpp (working copy) @@ -68,7 +68,8 @@ m_transparent(false), m_revealHidden(false), m_displaying(false), m_osd(osd), - m_header_changed(false), m_page_changed(false) + m_header_changed(false), m_page_changed(false), + m_osd_changed(false) { m_unbiasedrect = bias(m_displayrect, wmult, hmult); @@ -89,7 +90,7 @@ */ void OSDTypeTeletext::Reset(void) { - QMutexLocker locker(&m_lock); + OSDTypeTeletext::OSDUpdateLocker locker(this); for (uint mag = 0; mag < 8; mag++) { @@ -129,7 +130,7 @@ const unsigned char* buf, int vbimode, int lang, int flags) { - QMutexLocker locker(&m_lock); + OSDTypeTeletext::OSDUpdateLocker locker(this); int magazine = MAGAZINE(page); if (magazine < 1 || magazine > 8) @@ -189,12 +190,12 @@ for (uint j = 8; j < 40; j++) ttpage->data[0][j] = m_bitswap[buf[j]]; } - else + else { memcpy(ttpage->data[0]+0, buf, 40); } - - if ( !(ttpage->flags & TP_INTERRUPTED_SEQ)) + + if ( !(ttpage->flags & TP_INTERRUPTED_SEQ)) { memcpy(m_header, ttpage->data[0], 40); HeaderUpdated(ttpage->data[0],ttpage->lang); @@ -204,10 +205,10 @@ /** \fn OSDTypeTeletext::AddTeletextData(int,int,const unsigned char*,int) * \brief Adds Teletext Data from TeletextDecoder */ -void OSDTypeTeletext::AddTeletextData(int magazine, int row, +void OSDTypeTeletext::AddTeletextData(int magazine, int row, const unsigned char* buf, int vbimode) { - QMutexLocker locker(&m_lock); + OSDTypeTeletext::OSDUpdateLocker locker(this); int b1, b2, b3, err; @@ -227,8 +228,8 @@ { for (uint j = 0; j < 40; j++) ttpage->data[row][j] = m_bitswap[buf[j]]; - } - else + } + else { memcpy(ttpage->data[row], buf, 40); } @@ -322,12 +323,18 @@ return; m_page_changed = true; - m_osd->UpdateTeletext(); + m_osd_changed = true; +// note: We cannot call UpdateTeletext from here since it will try to get the +// osdlock. The problem with this is that the OSD::Display might already +// be active and have called our Draw function and hence is pending the +// m_lock being freed. Since the OSD::Display uses the osdlock, our call +// to the UpdateTeletext would result in a semaphore deadlock. +// m_osd->UpdateTeletext(); } /** \fn OSDTypeTeletext::HeaderUpdated(unsigned char*,int) * \brief Updates the header (given in page with language lang) - * + * * \param page Pointer to the header which should be displayed * \param lang Language of the header * @@ -359,7 +366,7 @@ * * \param page Page number * \param direction find page before or after the given page - * \return TeletextPage (NULL if not found) + * \return TeletextPage (NULL if not found) */ const TeletextPage *OSDTypeTeletext::FindPageInternal( int page, int direction) const @@ -412,7 +419,7 @@ * \param subpage Subpage number (if set to -1, find the first subpage) * \param direction find page before or after the given page * (only if Subpage is not -1) - * \return TeletextSubPage (NULL if not found) + * \return TeletextSubPage (NULL if not found) */ const TeletextSubPage *OSDTypeTeletext::FindSubPageInternal( int page, int subpage, int direction) const @@ -479,7 +486,7 @@ */ void OSDTypeTeletext::KeyPress(uint key) { - QMutexLocker locker(&m_lock); + OSDTypeTeletext::OSDUpdateLocker locker(this); int newPage = m_curpage; int newSubPage = m_cursubpage; @@ -523,7 +530,7 @@ newSubPage = -1; m_curpage_showheader = true; break; - } + } case TTKey::kPrevPage: { @@ -665,7 +672,7 @@ */ void OSDTypeTeletext::SetPage(int page, int subpage) { - QMutexLocker locker(&m_lock); + OSDTypeTeletext::OSDUpdateLocker locker(this); if (page < 0x100 || page > 0x899) return; @@ -796,7 +803,7 @@ } /** \fn OSDTypeTeletext::DrawCharacter(OSDSurface*,int,int,QChar,int) const - * \brief Draws a character at posistion x, y + * \brief Draws a character at posistion x, y * * \param x X position (40 cols) * \param y Y position (25 rows) @@ -1109,7 +1116,7 @@ void OSDTypeTeletext::Reinit(float wmult, float hmult) { - QMutexLocker locker(&m_lock); + OSDTypeTeletext::OSDUpdateLocker locker(this); m_displayrect = bias(m_unbiasedrect, wmult, hmult); m_tt_colspace = m_displayrect.width() / kTeletextColumns; @@ -1232,3 +1239,45 @@ } } +/* + **************************************************************************** + * + * OSDUpdateLocker - helper class to the OSDTypeTeletext. + * This class is used to lock the m_lock semaphore when + * there is a chance that the locked code will result in the + * OSD::UpdateTeletext() function being called. It's purpose + * is to lock the semaphore and once the locked code has + * finished to check for a request to call OSD::UpdateTeletext(). + * If required, the m_lock is released and the required call made + * + * This is to overcome the possible semaphore deadlock as follows: + * + * -Teletext data arrives -> locks m_lock + * -While the teletext data is being processed the XMV request an OSD update display + * -The OSD update display will lock the osdlock + * -The OSD update can results in the Teletext:Draw function being call and hence the + * OSD update is now waiting on m_lock being released to continue it's drawing process + * -If the processing of the teletext data result in the function OSD::UpdateTeletext + * being called, this function will try to get the osdlock. + * -This results in the classic semaphore deadlock and hence all OSD update cease. + * + ***************************************************************************** + */ +OSDTypeTeletext::OSDUpdateLocker::OSDUpdateLocker(OSDTypeTeletext *parent) + :parent(parent) +{ + parent->m_lock.lock(); +} + +OSDTypeTeletext::OSDUpdateLocker::~OSDUpdateLocker(void) +{ + if (parent->m_osd_changed == true) // see if the osd has to be requested to redraw + { + parent->m_osd_changed = false; // clear the flag + parent->m_lock.unlock(); // and remove the m_lock + parent->m_osd->UpdateTeletext(); // now it is safe to do the OSD update + return; + } + parent->m_lock.unlock(); // normal exit. Will result in the m_lock being released. +} + Index: libs/libmythtv/osdtypeteletext.h =================================================================== --- libs/libmythtv/osdtypeteletext.h (revision 13437) +++ libs/libmythtv/osdtypeteletext.h (working copy) @@ -170,7 +170,17 @@ const TeletextPage *FindPageInternal(int,int) const; private: + class OSDUpdateLocker + { + public: + OSDUpdateLocker(OSDTypeTeletext *parent); + ~OSDUpdateLocker(void); + private: + OSDTypeTeletext *parent; + }; + QMutex m_lock; + QRect m_displayrect; QRect m_unbiasedrect; @@ -209,6 +219,7 @@ uint8_t m_header[40]; mutable bool m_header_changed; mutable bool m_page_changed; + mutable bool m_osd_changed; TeletextMagazine m_magazines[8]; unsigned char m_bitswap[256];