From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH net] net: stmmac: fix completely hung TX when using TSO Date: Tue, 6 Jun 2017 07:31:23 -0700 Message-ID: <284161d4-760f-0dd9-0363-c8e13750fba8@gmail.com> References: <20170606072501.16560-1-niklas.cassel@axis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Niklas Cassel , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Niklas Cassel , Giuseppe Cavallaro , Alexandre Torgue Return-path: In-Reply-To: <20170606072501.16560-1-niklas.cassel@axis.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 06/06/2017 12:25 AM, Niklas Cassel wrote: > stmmac_tso_allocator can fail to set the Last Descriptor bit > on a descriptor that actually was the last descriptor. > > This happens when the buffer of the last descriptor ends > up having a size of exactly TSO_MAX_BUFF_SIZE. > > When the IP eventually reaches the next last descriptor, > which actually has the bit set, the DMA will hang. > > When the DMA hangs, we get a tx timeout, however, > since stmmac does not do a complete reset of the IP > in stmmac_tx_timeout, we end up in a state with > completely hung TX. > > Signed-off-by: Niklas Cassel This should have: Fixes: f748be531d70 ("stmmac: support new GMAC4") right? > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index 68a188e74c54..440bea049a7f 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -2723,7 +2723,7 @@ static void stmmac_tso_allocator(struct stmmac_priv *priv, unsigned int des, > > priv->hw->desc->prepare_tso_tx_desc(desc, 0, buff_size, > 0, 1, > - (last_segment) && (buff_size < TSO_MAX_BUFF_SIZE), > + (last_segment) && (tmp_len <= TSO_MAX_BUFF_SIZE), > 0, 0); > > tmp_len -= TSO_MAX_BUFF_SIZE; > -- Florian