第二十六篇:USB3.0高帶寬ISO(48KBytes/125us)實戰
USB3.1技術已經推出, 10Gbps的速率足以滿足數據, HD視頻傳輸的要求.
要步入USB3.1的研發, 還得將USB3.0的基礎打紮實.
微軟提供的SUPER MUTT僅僅包括一個接口0, 其下有兩個ALT, ALT 1與ALT 2, 分別包括了兩對ISO IN/OUT端點, 只是, 僅僅有ALT 2下的ISO OUT EP的bMaxBurst為1, 而其他三個ISO EP的bMaxBurst均為0, 而全部的ISO EP的Mult均為0.
即僅僅有一個ISO EP支持2KBytes/125us的能力, 其余三個ISO EP僅僅支持1KBytes/125us的能力,?技術上來講,
遠遠未達到高帶寬(48KBytes/125us)的上限.
這種設備,甚至都不如一個高帶寬的USB2.0的設備(3KBytes/125us),用來衡量系統中USB3.0 xHCI HOST的高帶寬能力也就無從談起了.
於是, 利用自開發的USB3.0 silicon, 對設備端驅動稍作改動, 經過Lecory Advisor T3 USB3.0分析儀的驗證, 證明設備端的ISO EP具有接收與發送48KBytes/125us的能力.
接下來, 則須要用該設備來驗證xHCI USB3.0 HOST的ISO高帶寬能力.
測試平臺為INTEL xHCI USB3.0 HOST, Win8 USB3 STACK.
先給出測試結果:
(1.1) HOST發送48*8KBYTES的數據
ISO MaxPacketSize = 49152
000000830.01842206read-write irp failed with status C0000001
000000850.01842534urb
header status C0000B00
00000089 0.01843355IsoPacket[0].offset = 0 ? ? ? ? ? IsoPacket[0].Length = 49152 IsoPacket[0].Status = c0030000
00000091 0.01843889IsoPacket[1].offset = 49152 ? IsoPacket[1].Length = 49152 IsoPacket[1].Status = c0030000
00000093 0.01844382
00000095 0.01844915IsoPacket[3].offset = 147456 IsoPacket[3].Length = 49152 IsoPacket[3].Status = c0030000
00000097 0.01846065IsoPacket[4].offset = 196608 IsoPacket[4].Length = 49152 IsoPacket[4].Status = c0030000
00000099 0.01846393IsoPacket[5].offset = 245760 IsoPacket[5].Length = 49152 IsoPacket[5].Status = c0030000
00000101 0.01846763IsoPacket[6].offset = 294912 IsoPacket[6].Length = 49152 IsoPacket[6].Status = c0030000
00000103 0.01847091IsoPacket[7].offset = 344064 IsoPacket[7].Length = 49152 IsoPacket[7].Status = c0030000
Total data transferred = 0(dec), 0(hex)
(1.2)??HOST接收48*8KBYTES的數據
000001690.02440798IsoPacket[0].offset
= 0 ? ? ? ? ? IsoPacket[0].Length = 49152 ? ? IsoPacket[0].Status = 0
00000171 0.02441290IsoPacket[1].offset = 49152 ? IsoPacket[1].Length = 49152 ? ? IsoPacket[1].Status = 0
00000173 0.02441824IsoPacket[2].offset = 98304 ? IsoPacket[2].Length = 0 ? ? ? ? ? ? IsoPacket[2].Status = c0030000
00000175 0.02442317IsoPacket[3].offset = 147456 IsoPacket[3].Length = 0 ? ? ? ? ? ? IsoPacket[3].Status = c0030000
00000177 0.02442850IsoPacket[4].offset = 196608 IsoPacket[4].Length = 49152 ? ? IsoPacket[4].Status = c0030000
00000179 0.02443343IsoPacket[5].offset = 245760 IsoPacket[5].Length = 0 ? ? ? ? ? ? IsoPacket[5].Status = c0030000
00000181 0.02444533IsoPacket[6].offset = 294912 IsoPacket[6].Length = 0 ? ? ? ? ? ? IsoPacket[6].Status = c0030000
00000183 0.02444821IsoPacket[7].offset = 344064 IsoPacket[7].Length = 49152 ? ? IsoPacket[7].Status = 0
這裏比較有意思的是:
8個包中, 有三個(0, 1, 7)是成功傳輸了48K的, 另一個盡管也傳輸了48K, 但系統USB3.0 STACK覺得該ISO PACKET(4)是不成功的.
這個不成功的原因, 後文中會解釋原因.
我所說的有意思是, USB3 STACK在填UrbIsochronousTransfer.TransferBufferLength的時候, 卻是4*48K, 而不是3*48K.
從以上USB分析儀中的數據能夠發現, 這8次寫失敗的原因有兩個:
1. xHCI HOST沒有在一個UFRAME中將數據發完,
2. XHCI HOST根本沒有發數據, 甚至都沒有在這個UFRAME中發出PING
歸結起來, 就是系統USB SUBSYSTEM, 甚至包括MEMORY CONTROLLER, 系統總線等一系列的因素所導致.
對於讀成功的情況, 則是在一個UFRAME中, XHCI HOST引發了(32+16)個1K的包的讀.
對於不成功的情況, 則是UFRAME中, XHCI HOST沒有發出ACK IN來讀取設備端的數據, 也甚至連PING都沒有發出.
(2.1) 48K*1寫:
00000082
0.00891627 read-write irp failed with status C0000001
00000084 0.00891914
urb header status C0000B00
00000088 0.00892735
IsoPacket[0].offset = 0 ? ? ? ? ? IsoPacket[0].Length = 49152 IsoPacket[0].Status = c0030000
00000090 0.00893269
IsoPacket[1].offset = 49152 ? IsoPacket[1].Length = 0 ? ? ? ? IsoPacket[1].Status = c0020000
00000092 0.00893803
IsoPacket[2].offset = 98304 ? IsoPacket[2].Length = 0 ? ? ? ? IsoPacket[2].Status = c0020000
00000094 0.00894295
IsoPacket[3].offset = 147456 IsoPacket[3].Length = 0 ? ? ? ? IsoPacket[3].Status = c0020000?
00000096 0.00895527
IsoPacket[4].offset = 196608 IsoPacket[4].Length = 0 ? ? ? ? IsoPacket[4].Status = c0020000
00000098 0.00895855
IsoPacket[5].offset = 245760 IsoPacket[5].Length = 0 ? ? ? ? IsoPacket[5].Status = c0020000
00000100 0.00896184
IsoPacket[6].offset = 294912 IsoPacket[6].Length = 0 ? ? ? ? IsoPacket[6].Status = c0020000
00000102 0.00896471
IsoPacket[7].offset = 344064 IsoPacket[7].Length = 0 ? ? ? ? IsoPacket[7].Status = c0020000
00000110 0.00897498
Total data transferred = 0(dec), 0(hex)
當中, 寫沒成功, 原因與48*8K同樣, 沒有在一個UFRAME將數據發完.
後面的ERROR CODE?c0020000並不是真正的錯誤, 而是上層沒有數據可發導致.
(2.2)48K*1讀:
00000168
0.01482911 IsoPacket[0].offset = 0 ? ? ? ? ? IsoPacket[0].Length = 49152 ? IsoPacket[0].Status = 0
00000170 0.01483404
IsoPacket[1].offset = 49152 ? IsoPacket[1].Length = 0 ? ? ? ? ? IsoPacket[1].Status = c0030000
00000172 0.01483938
IsoPacket[2].offset = 98304 ? IsoPacket[2].Length = 0 ? ? ? ? ? IsoPacket[2].Status = c0030000
00000174 0.01484389
IsoPacket[3].offset = 147456 IsoPacket[3].Length = 49152 ? IsoPacket[3].Status = 0
00000176 0.01485498
IsoPacket[4].offset = 196608 IsoPacket[4].Length = 0 ? ? ? ? ? IsoPacket[4].Status = c0030000
00000178 0.01485826
IsoPacket[5].offset = 245760 IsoPacket[5].Length = 0 ? ? ? ? ? IsoPacket[5].Status = c0030000
00000182 0.01486196
IsoPacket[6].offset = 294912 IsoPacket[6].Length = 49152 ? IsoPacket[6].Status = 0
00000186 0.01486524
IsoPacket[7].offset = 344064 IsoPacket[7].Length = 0 ? ? ? ? ? IsoPacket[7].Status = c0030000
情況和48K*8情況同樣.
僅僅是這裏沒有出現既傳輸了數據, 又是出錯的情況.
(3.1) 32K*8 WRITE
(3.2) 32K*8 READ
都成功.
總結:
INTEL的xHCI系統加上WIN8的USB3 STACK能夠達到32KB/UFRAME的能力, 但不能達到48KB/UFRAME的能力.
第二十六篇:USB3.0高帶寬ISO(48KBytes/125us)實戰