On 02/02/2018 01:50 AM, Pkshih wrote:
Hi James,

In my experiment, unaligned-word-access may get wrong values that
are different from the value by byte-access. Actually, it can simply
verified by using 'lspci' to check PCI configuration space.

DBI read 0x70f:
_rtl8821ae_dbi_read:1127 r8 0x34f = 0x0017
_rtl8821ae_dbi_read:1131 r8 0x350 = 0x000c
_rtl8821ae_dbi_read:1136 r16 0x350 = 0xffff

DBI read 0x719:
_rtl8821ae_dbi_read:1127 r8 0x34d = 0x0000
_rtl8821ae_dbi_read:1131 r8 0x34e = 0x0002
_rtl8821ae_dbi_read:1136 r16 0x34e = 0x0200

According to the wrong and original value of 0x70f is 0xff, I think
larger L1 latency 0x70f[5:3] may be helpful. Please help to try
below patch. If it works, quirk table won't be necessary.


diff --git a/rtl8821ae/hw.c b/rtl8821ae/hw.c
index 7d43ba002..e53af06ed 100644
--- a/rtl8821ae/hw.c
+++ b/rtl8821ae/hw.c
@@ -1123,7 +1123,8 @@ static u8 _rtl8821ae_dbi_read(struct rtl_priv *rtlpriv, 
u16 addr)
        if (0 == tmp) {
                read_addr = REG_DBI_RDATA + addr % 4;
-               ret = rtl_read_word(rtlpriv, read_addr);
+               ret = rtl_read_byte(rtlpriv, read_addr);
        return ret;
@@ -1165,7 +1166,7 @@ static void _rtl8821ae_enable_aspm_back_door(struct 
ieee80211_hw *hw)
tmp = _rtl8821ae_dbi_read(rtlpriv, 0x70f);
-       _rtl8821ae_dbi_write(rtlpriv, 0x70f, tmp | BIT(7));
+       _rtl8821ae_dbi_write(rtlpriv, 0x70f, tmp | BIT(7) | 0x38);
tmp = _rtl8821ae_dbi_read(rtlpriv, 0x719);
        _rtl8821ae_dbi_write(rtlpriv, 0x719, tmp | BIT(3) | BIT(4));


This patch works perfectly on my x86_64 system. With it, the interface handled a 10 million count flood ping with <1000 packets dropped. It has now been running for at least 11 hours. Good work.

Can you explain that magic 0x38? I'm quite sure that Kalle will not accept the patch as is. He already thinks that rtlwifi and friends already have too many magic numbers.


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