4.4-stable review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
commit c9bd28233b6d0d82ac3ba0215723be0a8262c39c upstream.
irda_get_mtt() returns a hardcoded '10000' in some cases, and with gcc-7, we get a build error because this triggers a compile-time check in udelay():
drivers/net/irda/w83977af_ir.o: In function `w83977af_hard_xmit': w83977af_ir.c:(.text.w83977af_hard_xmit+0x14c): undefined reference to `__bad_udelay'
Older compilers did not run into this because they either did not completely inline the irda_get_mtt() or did not consider the 10000 value a constant expression.
The code has been wrong since the start of git history.
Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: David S. Miller davem@davemloft.net Cc: Guenter Roeck linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/net/irda/w83977af_ir.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/net/irda/w83977af_ir.c +++ b/drivers/net/irda/w83977af_ir.c @@ -518,7 +518,9 @@ static netdev_tx_t w83977af_hard_xmit(st mtt = irda_get_mtt(skb); pr_debug("%s(%ld), mtt=%d\n", __func__ , jiffies, mtt); - if (mtt) + if (mtt > 1000) + mdelay(mtt/1000); + else if (mtt) udelay(mtt);
/* Enable DMA interrupt */