Niklas Cassel 1e88f6e01b net: stmmac: make dwmac4_release_tx_desc() clear all descriptor fields ... Make dwmac4_release_tx_desc() clear all descriptor fields, not just TDES2 and TDES3. I'm suspecting that TDES0 and TDES1 wasn't cleared because the DMA engine uses them to store the tx hardware timestamp (if PTP is enabled). However, stmmac_tx_clean() calls stmmac_get_tx_hwtstamp(), which reads and saves the timestamp, before it calls release_tx_desc(), so this is not an issue. stmmac_xmit() and stmmac_tso_xmit() both always overwrite TDES0, however, stmmac_tso_xmit() sometimes sets TDES1, and since neither stmmac_xmit() nor stmmac_tso_xmit() explicitly clears TDES1, both functions might reuse a DMA descriptor with old TDES1 data. I haven't observed any misbehavior even though TDES1 sometimes point to an old skb, however, explicitly clearing both TDES0 and TDES1 in dwmac4_release_tx_desc() minimizes the chances of undefined behavior. Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2018-02-27 14:28:10 -05:00
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stmmac	net: stmmac: make dwmac4_release_tx_desc() clear all descriptor fields	2018-02-27 14:28:10 -05:00
Kconfig	stmicro: add more information to Kconfig	2017-01-18 12:12:04 -05:00
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