Commit 635526b8 authored by Sasha Neftin's avatar Sasha Neftin Committed by Greg Kroah-Hartman

e1000e: fix the use of magic numbers for buffer overrun issue

commit c0f4b163 upstream.

This is a follow on to commit b10effb9 ("fix buffer overrun while the
 I219 is processing DMA transactions") to address David Laights concerns
about the use of "magic" numbers.  So define masks as well as add
additional code comments to give a better understanding of what needs to
be done to avoid a buffer overrun.
Signed-off-by: default avatarSasha Neftin <>
Reviewed-by: default avatarAlexander H Duyck <>
Reviewed-by: default avatarDima Ruinskiy <>
Reviewed-by: default avatarRaanan Avargil <>
Tested-by: default avatarAaron Brown <>
Signed-off-by: default avatarJeff Kirsher <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent c48f3c04
......@@ -113,7 +113,8 @@
#define NVM_SIZE_MULTIPLIER 4096 /*multiplier for NVMS field */
#define E1000_FLASH_BASE_ADDR 0xE000 /*offset of NVM access regs */
#define E1000_CTRL_EXT_NVMVS 0x3 /*NVM valid sector */
#define E1000_TARC0_CB_MULTIQ_3_REQ (1 << 28 | 1 << 29)
#define E1000_TARC0_CB_MULTIQ_3_REQ 0x30000000
#define E1000_TARC0_CB_MULTIQ_2_REQ 0x20000000
#define E1000_ICH_RAR_ENTRIES 7
......@@ -3030,9 +3030,12 @@ static void e1000_configure_tx(struct e1000_adapter *adapter)
ew32(IOSFPC, reg_val);
reg_val = er32(TARC(0));
/* SPT and KBL Si errata workaround to avoid Tx hang */
reg_val &= ~BIT(28);
reg_val |= BIT(29);
/* SPT and KBL Si errata workaround to avoid Tx hang.
* Dropping the number of outstanding requests from
* 3 to 2 in order to avoid a buffer overrun.
reg_val &= ~E1000_TARC0_CB_MULTIQ_3_REQ;
reg_val |= E1000_TARC0_CB_MULTIQ_2_REQ;
ew32(TARC(0), reg_val);
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