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| author | Imre Kaloz <kaloz@openwrt.org> | 2010-08-09 11:27:14 +0000 |
|---|---|---|
| committer | Imre Kaloz <kaloz@openwrt.org> | 2010-08-09 11:27:14 +0000 |
| commit | 16478f7dd6f30eb6580470e026ab32fdd572e2af (patch) | |
| tree | 567f408ee5be92378e092d4f8346853b816241a7 | |
| parent | 0f5d0f69ab14d9817c16147cef0a1a537a1cc8c4 (diff) | |
| download | mtk-20170518-16478f7dd6f30eb6580470e026ab32fdd572e2af.zip mtk-20170518-16478f7dd6f30eb6580470e026ab32fdd572e2af.tar.gz mtk-20170518-16478f7dd6f30eb6580470e026ab32fdd572e2af.tar.bz2 | |
workaround serial hang with SMP enabled
SVN-Revision: 22557
| -rw-r--r-- | target/linux/cns3xxx/patches-2.6.31/210-cns3xxx_smp_serial_fix.patch | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/target/linux/cns3xxx/patches-2.6.31/210-cns3xxx_smp_serial_fix.patch b/target/linux/cns3xxx/patches-2.6.31/210-cns3xxx_smp_serial_fix.patch new file mode 100644 index 0000000..a9b45ae --- /dev/null +++ b/target/linux/cns3xxx/patches-2.6.31/210-cns3xxx_smp_serial_fix.patch @@ -0,0 +1,39 @@ +--- a/drivers/serial/8250.c ++++ b/drivers/serial/8250.c +@@ -1743,6 +1743,7 @@ static void serial8250_backup_timeout(un + unsigned int iir, ier = 0, lsr; + unsigned long flags; + ++ spin_lock_irqsave(&up->port.lock, flags); + /* + * Must disable interrupts or else we risk racing with the interrupt + * based handler. +@@ -1760,10 +1761,8 @@ static void serial8250_backup_timeout(un + * the "Diva" UART used on the management processor on many HP + * ia64 and parisc boxes. + */ +- spin_lock_irqsave(&up->port.lock, flags); + lsr = serial_in(up, UART_LSR); + up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; +- spin_unlock_irqrestore(&up->port.lock, flags); + if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) && + (!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) && + (lsr & UART_LSR_THRE)) { +@@ -1771,12 +1770,14 @@ static void serial8250_backup_timeout(un + iir |= UART_IIR_THRI; + } + +- if (!(iir & UART_IIR_NO_INT)) +- serial8250_handle_port(up); +- + if (is_real_interrupt(up->port.irq)) + serial_out(up, UART_IER, ier); + ++ spin_unlock_irqrestore(&up->port.lock, flags); ++ ++ if (!(iir & UART_IIR_NO_INT)) ++ serial8250_handle_port(up); ++ + /* Standard timer interval plus 0.2s to keep the port running */ + mod_timer(&up->timer, + jiffies + poll_timeout(up->port.timeout) + HZ / 5); |