* [PATCH -next] thunderbolt: Add quirk to reset host interface on DMA path teardown for AMD USB4 routers
@ 2026-08-04 12:26 Basavaraj Natikar
2026-08-05 3:49 ` Mika Westerberg
0 siblings, 1 reply; 3+ messages in thread
From: Basavaraj Natikar @ 2026-08-04 12:26 UTC (permalink / raw)
To: andreas.noever, westeri, YehezkelShB, linux-usb
Cc: Mario.Limonciello, Basavaraj Natikar, Sanath S
Some AMD USB4 host routers have a bug in the Host Interface where
DMA path setup and teardown cycles may cause the Tx ring to hang.
Fix this by issuing a Host Interface Reset on every DMA path teardown
for affected routers. The Host Interface Reset brings the registers in
the memory BAR to their default state and clears the End-to-End Flow
Control state, preventing the hang condition.
Co-developed-by: Sanath S <Sanath.S@amd.com>
Signed-off-by: Sanath S <Sanath.S@amd.com>
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
---
drivers/thunderbolt/nhi.c | 48 ++++++++++++++++++++++++++++++++++
drivers/thunderbolt/nhi_regs.h | 4 +++
drivers/thunderbolt/quirks.c | 16 ++++++++++++
drivers/thunderbolt/tb.c | 7 +++++
drivers/thunderbolt/tb.h | 3 +++
5 files changed, 78 insertions(+)
diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index 383a36212f70..0865cab582e7 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -1160,6 +1160,54 @@ static void nhi_reset(struct tb_nhi *nhi)
dev_warn(nhi->dev, "timeout resetting host router\n");
}
+/**
+ * nhi_host_interface_reset() - Issue a host interface reset
+ * @nhi: Pointer to the NHI structure
+ *
+ * Resets the Host Interface by setting the RST bit in the Host Interface
+ * Reset register. This brings the registers in the memory BAR to their
+ * default state and clears the End-to-End Flow Control state.
+ *
+ * The caller must ensure that the control channel (Ring 0) is stopped
+ * before calling this function, since the reset clears ring state.
+ * The caller is responsible for restarting Ring 0 afterward.
+ *
+ * After setting the RST bit, waits for tHIReset (10 ms) for the reset
+ * to complete.
+ */
+static void nhi_host_interface_reset(struct tb_nhi *nhi)
+{
+ struct device *dev = nhi->dev;
+ u32 val;
+
+ val = ioread32(nhi->iobase + REG_CAPS);
+ /* Host Interface Reset only applies to Ver. 1 routers */
+ if (FIELD_GET(REG_CAPS_VERSION_MASK, val) >= REG_CAPS_VERSION_2)
+ return;
+
+ dev_dbg(dev, "issuing host interface reset\n");
+
+ iowrite32(REG_HOST_INTERFACE_RESET_RST,
+ nhi->iobase + REG_HOST_INTERFACE_RESET);
+
+ /* Wait for tHIReset (10 ms) for the reset to complete */
+ usleep_range(10000, 20000);
+}
+
+/**
+ * tb_nhi_host_interface_reset() - Reset host interface with control channel
+ * @tb: Pointer to the thunderbolt domain
+ *
+ * Stops the control channel, issues a Host Interface Reset, and restarts
+ * the control channel.
+ */
+void tb_nhi_host_interface_reset(struct tb *tb)
+{
+ tb_ctl_stop(tb->ctl);
+ nhi_host_interface_reset(tb->nhi);
+ tb_ctl_start(tb->ctl);
+}
+
static struct tb *nhi_select_cm(struct tb_nhi *nhi)
{
struct tb *tb;
diff --git a/drivers/thunderbolt/nhi_regs.h b/drivers/thunderbolt/nhi_regs.h
index d6a197fabc74..99df60b6db36 100644
--- a/drivers/thunderbolt/nhi_regs.h
+++ b/drivers/thunderbolt/nhi_regs.h
@@ -115,6 +115,10 @@ struct ring_desc {
#define REG_CAPS_VERSION_MASK GENMASK(23, 16)
#define REG_CAPS_VERSION_2 0x40
+/* Host Interface Reset - resets TX/RX rings and E2E flow control counters */
+#define REG_HOST_INTERFACE_RESET 0x39858
+#define REG_HOST_INTERFACE_RESET_RST BIT(0)
+
#define REG_DMA_MISC 0x39864
#define REG_DMA_MISC_INT_AUTO_CLEAR BIT(2)
#define REG_DMA_MISC_DISABLE_AUTO_CLEAR BIT(17)
diff --git a/drivers/thunderbolt/quirks.c b/drivers/thunderbolt/quirks.c
index 9f7914ac2f48..cc04d0873931 100644
--- a/drivers/thunderbolt/quirks.c
+++ b/drivers/thunderbolt/quirks.c
@@ -52,6 +52,12 @@ static void quirk_block_rpm_in_redrive(struct tb_switch *sw)
tb_sw_dbg(sw, "preventing runtime PM in DP redrive mode\n");
}
+static void quirk_host_interface_reset(struct tb_switch *sw)
+{
+ sw->quirks |= QUIRK_HOST_INTERFACE_RESET;
+ tb_sw_dbg(sw, "enabling host interface reset on DMA path teardown\n");
+}
+
struct tb_quirk {
u16 hw_vendor_id;
u16 hw_device_id;
@@ -114,6 +120,16 @@ static const struct tb_quirk tb_quirks[] = {
{ 0x0438, 0x0209, 0x0000, 0x0000, quirk_clx_disable },
{ 0x0438, 0x020a, 0x0000, 0x0000, quirk_clx_disable },
{ 0x0438, 0x020b, 0x0000, 0x0000, quirk_clx_disable },
+ /*
+ * AMD USB4 host routers may hang the Tx ring after repeated
+ * DMA path teardowns. Issue a Host Interface Reset on each
+ * teardown to prevent the hang.
+ */
+ { 0x0438, 0x020d, 0x0000, 0x0000, quirk_host_interface_reset },
+ { 0x0438, 0x020e, 0x0000, 0x0000, quirk_host_interface_reset },
+ { 0x0438, 0x020f, 0x0000, 0x0000, quirk_host_interface_reset },
+ { 0x0438, 0x0210, 0x0000, 0x0000, quirk_host_interface_reset },
+ { 0x0438, 0x0211, 0x0000, 0x0000, quirk_host_interface_reset },
};
/**
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 47753a5c0f2e..d40cc9e57364 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -2395,6 +2395,13 @@ static void __tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
* the same host router USB4 downstream port.
*/
tb_enable_clx(sw);
+
+ /*
+ * Some host routers may hang the Tx ring after DMA path teardowns.
+ * Issue a Host Interface Reset to prevent it.
+ */
+ if (tb->root_switch->quirks & QUIRK_HOST_INTERFACE_RESET)
+ tb_nhi_host_interface_reset(tb);
}
static int tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 4373336d9425..d21feb631f3e 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -26,6 +26,8 @@
#define QUIRK_NO_CLX BIT(1)
/* Need to keep power on while USB4 port is in redrive mode */
#define QUIRK_KEEP_POWER_IN_DP_REDRIVE BIT(2)
+/* Reset Host Interface on DMA path teardown to prevent Tx ring hang */
+#define QUIRK_HOST_INTERFACE_RESET BIT(3)
/**
* struct tb_nvm - Structure holding NVM information
@@ -1507,6 +1509,7 @@ static inline bool usb4_port_device_is_offline(const struct usb4_port *usb4)
}
void tb_check_quirks(struct tb_switch *sw);
+void tb_nhi_host_interface_reset(struct tb *tb);
#ifdef CONFIG_ACPI
bool tb_acpi_add_links(struct tb_nhi *nhi);
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH -next] thunderbolt: Add quirk to reset host interface on DMA path teardown for AMD USB4 routers
2026-08-04 12:26 [PATCH -next] thunderbolt: Add quirk to reset host interface on DMA path teardown for AMD USB4 routers Basavaraj Natikar
@ 2026-08-05 3:49 ` Mika Westerberg
2026-08-05 11:10 ` Basavaraj Natikar
0 siblings, 1 reply; 3+ messages in thread
From: Mika Westerberg @ 2026-08-05 3:49 UTC (permalink / raw)
To: Basavaraj Natikar
Cc: andreas.noever, westeri, YehezkelShB, linux-usb,
Mario.Limonciello, Sanath S
Hi,
On Tue, Aug 04, 2026 at 05:56:38PM +0530, Basavaraj Natikar wrote:
> Some AMD USB4 host routers have a bug in the Host Interface where
> DMA path setup and teardown cycles may cause the Tx ring to hang.
>
> Fix this by issuing a Host Interface Reset on every DMA path teardown
> for affected routers. The Host Interface Reset brings the registers in
> the memory BAR to their default state and clears the End-to-End Flow
> Control state, preventing the hang condition.
>
> Co-developed-by: Sanath S <Sanath.S@amd.com>
> Signed-off-by: Sanath S <Sanath.S@amd.com>
> Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
> ---
> drivers/thunderbolt/nhi.c | 48 ++++++++++++++++++++++++++++++++++
> drivers/thunderbolt/nhi_regs.h | 4 +++
> drivers/thunderbolt/quirks.c | 16 ++++++++++++
> drivers/thunderbolt/tb.c | 7 +++++
> drivers/thunderbolt/tb.h | 3 +++
> 5 files changed, 78 insertions(+)
>
> diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
> index 383a36212f70..0865cab582e7 100644
> --- a/drivers/thunderbolt/nhi.c
> +++ b/drivers/thunderbolt/nhi.c
> @@ -1160,6 +1160,54 @@ static void nhi_reset(struct tb_nhi *nhi)
> dev_warn(nhi->dev, "timeout resetting host router\n");
> }
>
> +/**
> + * nhi_host_interface_reset() - Issue a host interface reset
> + * @nhi: Pointer to the NHI structure
> + *
> + * Resets the Host Interface by setting the RST bit in the Host Interface
> + * Reset register. This brings the registers in the memory BAR to their
> + * default state and clears the End-to-End Flow Control state.
> + *
> + * The caller must ensure that the control channel (Ring 0) is stopped
> + * before calling this function, since the reset clears ring state.
> + * The caller is responsible for restarting Ring 0 afterward.
> + *
> + * After setting the RST bit, waits for tHIReset (10 ms) for the reset
> + * to complete.
> + */
> +static void nhi_host_interface_reset(struct tb_nhi *nhi)
> +{
> + struct device *dev = nhi->dev;
> + u32 val;
> +
> + val = ioread32(nhi->iobase + REG_CAPS);
> + /* Host Interface Reset only applies to Ver. 1 routers */
> + if (FIELD_GET(REG_CAPS_VERSION_MASK, val) >= REG_CAPS_VERSION_2)
> + return;
> +
> + dev_dbg(dev, "issuing host interface reset\n");
> +
> + iowrite32(REG_HOST_INTERFACE_RESET_RST,
> + nhi->iobase + REG_HOST_INTERFACE_RESET);
> +
> + /* Wait for tHIReset (10 ms) for the reset to complete */
> + usleep_range(10000, 20000);
> +}
> +
> +/**
> + * tb_nhi_host_interface_reset() - Reset host interface with control channel
> + * @tb: Pointer to the thunderbolt domain
> + *
> + * Stops the control channel, issues a Host Interface Reset, and restarts
> + * the control channel.
> + */
> +void tb_nhi_host_interface_reset(struct tb *tb)
> +{
> + tb_ctl_stop(tb->ctl);
> + nhi_host_interface_reset(tb->nhi);
> + tb_ctl_start(tb->ctl);
> +}
> +
> static struct tb *nhi_select_cm(struct tb_nhi *nhi)
> {
> struct tb *tb;
> diff --git a/drivers/thunderbolt/nhi_regs.h b/drivers/thunderbolt/nhi_regs.h
> index d6a197fabc74..99df60b6db36 100644
> --- a/drivers/thunderbolt/nhi_regs.h
> +++ b/drivers/thunderbolt/nhi_regs.h
> @@ -115,6 +115,10 @@ struct ring_desc {
> #define REG_CAPS_VERSION_MASK GENMASK(23, 16)
> #define REG_CAPS_VERSION_2 0x40
>
> +/* Host Interface Reset - resets TX/RX rings and E2E flow control counters */
> +#define REG_HOST_INTERFACE_RESET 0x39858
> +#define REG_HOST_INTERFACE_RESET_RST BIT(0)
> +
> #define REG_DMA_MISC 0x39864
> #define REG_DMA_MISC_INT_AUTO_CLEAR BIT(2)
> #define REG_DMA_MISC_DISABLE_AUTO_CLEAR BIT(17)
> diff --git a/drivers/thunderbolt/quirks.c b/drivers/thunderbolt/quirks.c
> index 9f7914ac2f48..cc04d0873931 100644
> --- a/drivers/thunderbolt/quirks.c
> +++ b/drivers/thunderbolt/quirks.c
> @@ -52,6 +52,12 @@ static void quirk_block_rpm_in_redrive(struct tb_switch *sw)
> tb_sw_dbg(sw, "preventing runtime PM in DP redrive mode\n");
> }
>
> +static void quirk_host_interface_reset(struct tb_switch *sw)
> +{
> + sw->quirks |= QUIRK_HOST_INTERFACE_RESET;
> + tb_sw_dbg(sw, "enabling host interface reset on DMA path teardown\n");
> +}
> +
> struct tb_quirk {
> u16 hw_vendor_id;
> u16 hw_device_id;
> @@ -114,6 +120,16 @@ static const struct tb_quirk tb_quirks[] = {
> { 0x0438, 0x0209, 0x0000, 0x0000, quirk_clx_disable },
> { 0x0438, 0x020a, 0x0000, 0x0000, quirk_clx_disable },
> { 0x0438, 0x020b, 0x0000, 0x0000, quirk_clx_disable },
> + /*
> + * AMD USB4 host routers may hang the Tx ring after repeated
> + * DMA path teardowns. Issue a Host Interface Reset on each
> + * teardown to prevent the hang.
> + */
> + { 0x0438, 0x020d, 0x0000, 0x0000, quirk_host_interface_reset },
> + { 0x0438, 0x020e, 0x0000, 0x0000, quirk_host_interface_reset },
> + { 0x0438, 0x020f, 0x0000, 0x0000, quirk_host_interface_reset },
> + { 0x0438, 0x0210, 0x0000, 0x0000, quirk_host_interface_reset },
> + { 0x0438, 0x0211, 0x0000, 0x0000, quirk_host_interface_reset },
These quirks are for things inside USB4 fabric. Since this is the HI, we
have quirks for those in pci.c/nhi.c like QUIRK_AUTO_CLEAR_INT. Can you
make this one follow that convention instead?
> };
>
> /**
> diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
> index 47753a5c0f2e..d40cc9e57364 100644
> --- a/drivers/thunderbolt/tb.c
> +++ b/drivers/thunderbolt/tb.c
> @@ -2395,6 +2395,13 @@ static void __tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
> * the same host router USB4 downstream port.
> */
> tb_enable_clx(sw);
> +
> + /*
> + * Some host routers may hang the Tx ring after DMA path teardowns.
> + * Issue a Host Interface Reset to prevent it.
> + */
> + if (tb->root_switch->quirks & QUIRK_HOST_INTERFACE_RESET)
> + tb_nhi_host_interface_reset(tb);
> }
>
> static int tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
> diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
> index 4373336d9425..d21feb631f3e 100644
> --- a/drivers/thunderbolt/tb.h
> +++ b/drivers/thunderbolt/tb.h
> @@ -26,6 +26,8 @@
> #define QUIRK_NO_CLX BIT(1)
> /* Need to keep power on while USB4 port is in redrive mode */
> #define QUIRK_KEEP_POWER_IN_DP_REDRIVE BIT(2)
> +/* Reset Host Interface on DMA path teardown to prevent Tx ring hang */
> +#define QUIRK_HOST_INTERFACE_RESET BIT(3)
>
> /**
> * struct tb_nvm - Structure holding NVM information
> @@ -1507,6 +1509,7 @@ static inline bool usb4_port_device_is_offline(const struct usb4_port *usb4)
> }
>
> void tb_check_quirks(struct tb_switch *sw);
> +void tb_nhi_host_interface_reset(struct tb *tb);
Also we don't need to expose this then (and if it needs to be exposed it
belongs to nhi.h not here.).
>
> #ifdef CONFIG_ACPI
> bool tb_acpi_add_links(struct tb_nhi *nhi);
> --
> 2.34.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH -next] thunderbolt: Add quirk to reset host interface on DMA path teardown for AMD USB4 routers
2026-08-05 3:49 ` Mika Westerberg
@ 2026-08-05 11:10 ` Basavaraj Natikar
0 siblings, 0 replies; 3+ messages in thread
From: Basavaraj Natikar @ 2026-08-05 11:10 UTC (permalink / raw)
To: Mika Westerberg, Basavaraj Natikar
Cc: andreas.noever, westeri, YehezkelShB, linux-usb,
Mario.Limonciello, Sanath S
On 8/5/2026 9:19 AM, Mika Westerberg wrote:
> Hi,
>
> On Tue, Aug 04, 2026 at 05:56:38PM +0530, Basavaraj Natikar wrote:
>> Some AMD USB4 host routers have a bug in the Host Interface where
>> DMA path setup and teardown cycles may cause the Tx ring to hang.
>>
>> Fix this by issuing a Host Interface Reset on every DMA path teardown
>> for affected routers. The Host Interface Reset brings the registers in
>> the memory BAR to their default state and clears the End-to-End Flow
>> Control state, preventing the hang condition.
>>
>> Co-developed-by: Sanath S <Sanath.S@amd.com>
>> Signed-off-by: Sanath S <Sanath.S@amd.com>
>> Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
>> ---
>> drivers/thunderbolt/nhi.c | 48 ++++++++++++++++++++++++++++++++++
>> drivers/thunderbolt/nhi_regs.h | 4 +++
>> drivers/thunderbolt/quirks.c | 16 ++++++++++++
>> drivers/thunderbolt/tb.c | 7 +++++
>> drivers/thunderbolt/tb.h | 3 +++
>> 5 files changed, 78 insertions(+)
>>
>> diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
>> index 383a36212f70..0865cab582e7 100644
>> --- a/drivers/thunderbolt/nhi.c
>> +++ b/drivers/thunderbolt/nhi.c
>> @@ -1160,6 +1160,54 @@ static void nhi_reset(struct tb_nhi *nhi)
>> dev_warn(nhi->dev, "timeout resetting host router\n");
>> }
>>
>> +/**
>> + * nhi_host_interface_reset() - Issue a host interface reset
>> + * @nhi: Pointer to the NHI structure
>> + *
>> + * Resets the Host Interface by setting the RST bit in the Host Interface
>> + * Reset register. This brings the registers in the memory BAR to their
>> + * default state and clears the End-to-End Flow Control state.
>> + *
>> + * The caller must ensure that the control channel (Ring 0) is stopped
>> + * before calling this function, since the reset clears ring state.
>> + * The caller is responsible for restarting Ring 0 afterward.
>> + *
>> + * After setting the RST bit, waits for tHIReset (10 ms) for the reset
>> + * to complete.
>> + */
>> +static void nhi_host_interface_reset(struct tb_nhi *nhi)
>> +{
>> + struct device *dev = nhi->dev;
>> + u32 val;
>> +
>> + val = ioread32(nhi->iobase + REG_CAPS);
>> + /* Host Interface Reset only applies to Ver. 1 routers */
>> + if (FIELD_GET(REG_CAPS_VERSION_MASK, val) >= REG_CAPS_VERSION_2)
>> + return;
>> +
>> + dev_dbg(dev, "issuing host interface reset\n");
>> +
>> + iowrite32(REG_HOST_INTERFACE_RESET_RST,
>> + nhi->iobase + REG_HOST_INTERFACE_RESET);
>> +
>> + /* Wait for tHIReset (10 ms) for the reset to complete */
>> + usleep_range(10000, 20000);
>> +}
>> +
>> +/**
>> + * tb_nhi_host_interface_reset() - Reset host interface with control channel
>> + * @tb: Pointer to the thunderbolt domain
>> + *
>> + * Stops the control channel, issues a Host Interface Reset, and restarts
>> + * the control channel.
>> + */
>> +void tb_nhi_host_interface_reset(struct tb *tb)
>> +{
>> + tb_ctl_stop(tb->ctl);
>> + nhi_host_interface_reset(tb->nhi);
>> + tb_ctl_start(tb->ctl);
>> +}
>> +
>> static struct tb *nhi_select_cm(struct tb_nhi *nhi)
>> {
>> struct tb *tb;
>> diff --git a/drivers/thunderbolt/nhi_regs.h b/drivers/thunderbolt/nhi_regs.h
>> index d6a197fabc74..99df60b6db36 100644
>> --- a/drivers/thunderbolt/nhi_regs.h
>> +++ b/drivers/thunderbolt/nhi_regs.h
>> @@ -115,6 +115,10 @@ struct ring_desc {
>> #define REG_CAPS_VERSION_MASK GENMASK(23, 16)
>> #define REG_CAPS_VERSION_2 0x40
>>
>> +/* Host Interface Reset - resets TX/RX rings and E2E flow control counters */
>> +#define REG_HOST_INTERFACE_RESET 0x39858
>> +#define REG_HOST_INTERFACE_RESET_RST BIT(0)
>> +
>> #define REG_DMA_MISC 0x39864
>> #define REG_DMA_MISC_INT_AUTO_CLEAR BIT(2)
>> #define REG_DMA_MISC_DISABLE_AUTO_CLEAR BIT(17)
>> diff --git a/drivers/thunderbolt/quirks.c b/drivers/thunderbolt/quirks.c
>> index 9f7914ac2f48..cc04d0873931 100644
>> --- a/drivers/thunderbolt/quirks.c
>> +++ b/drivers/thunderbolt/quirks.c
>> @@ -52,6 +52,12 @@ static void quirk_block_rpm_in_redrive(struct tb_switch *sw)
>> tb_sw_dbg(sw, "preventing runtime PM in DP redrive mode\n");
>> }
>>
>> +static void quirk_host_interface_reset(struct tb_switch *sw)
>> +{
>> + sw->quirks |= QUIRK_HOST_INTERFACE_RESET;
>> + tb_sw_dbg(sw, "enabling host interface reset on DMA path teardown\n");
>> +}
>> +
>> struct tb_quirk {
>> u16 hw_vendor_id;
>> u16 hw_device_id;
>> @@ -114,6 +120,16 @@ static const struct tb_quirk tb_quirks[] = {
>> { 0x0438, 0x0209, 0x0000, 0x0000, quirk_clx_disable },
>> { 0x0438, 0x020a, 0x0000, 0x0000, quirk_clx_disable },
>> { 0x0438, 0x020b, 0x0000, 0x0000, quirk_clx_disable },
>> + /*
>> + * AMD USB4 host routers may hang the Tx ring after repeated
>> + * DMA path teardowns. Issue a Host Interface Reset on each
>> + * teardown to prevent the hang.
>> + */
>> + { 0x0438, 0x020d, 0x0000, 0x0000, quirk_host_interface_reset },
>> + { 0x0438, 0x020e, 0x0000, 0x0000, quirk_host_interface_reset },
>> + { 0x0438, 0x020f, 0x0000, 0x0000, quirk_host_interface_reset },
>> + { 0x0438, 0x0210, 0x0000, 0x0000, quirk_host_interface_reset },
>> + { 0x0438, 0x0211, 0x0000, 0x0000, quirk_host_interface_reset },
> These quirks are for things inside USB4 fabric. Since this is the HI, we
> have quirks for those in pci.c/nhi.c like QUIRK_AUTO_CLEAR_INT. Can you
> make this one follow that convention instead?
>
>> };
>>
>> /**
>> diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
>> index 47753a5c0f2e..d40cc9e57364 100644
>> --- a/drivers/thunderbolt/tb.c
>> +++ b/drivers/thunderbolt/tb.c
>> @@ -2395,6 +2395,13 @@ static void __tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
>> * the same host router USB4 downstream port.
>> */
>> tb_enable_clx(sw);
>> +
>> + /*
>> + * Some host routers may hang the Tx ring after DMA path teardowns.
>> + * Issue a Host Interface Reset to prevent it.
>> + */
>> + if (tb->root_switch->quirks & QUIRK_HOST_INTERFACE_RESET)
>> + tb_nhi_host_interface_reset(tb);
>> }
>>
>> static int tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
>> diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
>> index 4373336d9425..d21feb631f3e 100644
>> --- a/drivers/thunderbolt/tb.h
>> +++ b/drivers/thunderbolt/tb.h
>> @@ -26,6 +26,8 @@
>> #define QUIRK_NO_CLX BIT(1)
>> /* Need to keep power on while USB4 port is in redrive mode */
>> #define QUIRK_KEEP_POWER_IN_DP_REDRIVE BIT(2)
>> +/* Reset Host Interface on DMA path teardown to prevent Tx ring hang */
>> +#define QUIRK_HOST_INTERFACE_RESET BIT(3)
>>
>> /**
>> * struct tb_nvm - Structure holding NVM information
>> @@ -1507,6 +1509,7 @@ static inline bool usb4_port_device_is_offline(const struct usb4_port *usb4)
>> }
>>
>> void tb_check_quirks(struct tb_switch *sw);
>> +void tb_nhi_host_interface_reset(struct tb *tb);
> Also we don't need to expose this then (and if it needs to be exposed it
> belongs to nhi.h not here.).
Sure Mika, I'll address both in v2:
- move the quirk to the NHI - set nhi->quirks in nhi_pci_check_quirks()
by PCI ID, following the QUIRK_AUTO_CLEAR_INT convention.
- move the helper declaration to nhi.h (out of tb.h).
Will send v2 shortly.
Thanks,
--
Basavaraj
>
>>
>> #ifdef CONFIG_ACPI
>> bool tb_acpi_add_links(struct tb_nhi *nhi);
>> --
>> 2.34.1
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-08-05 11:10 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2026-08-04 12:26 [PATCH -next] thunderbolt: Add quirk to reset host interface on DMA path teardown for AMD USB4 routers Basavaraj Natikar
2026-08-05 3:49 ` Mika Westerberg
2026-08-05 11:10 ` Basavaraj Natikar
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