In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com --- drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) }
/* configure the endpoint descriptors ... */ - ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports); - ms_out_desc.bNumEmbMIDIJack = midi->in_ports; + ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports); + ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports); - ms_in_desc.bNumEmbMIDIJack = midi->out_ports; + ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports); + ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i;
On Wed, 29 Jan 2025 17:05:19 +0100, John Keeping wrote:
In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Are you sure that it's a correct change?
IIUC, the in_ports and out_ports parameters are for external IN and OUT jacks, where an external OUT jack is connected to an embedded IN jack, and an external IN jack is connected to an embedded OUT jack.
thanks,
Takashi
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com
drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) } /* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i; -- 2.48.1
On Wed, Jan 29, 2025 at 05:40:04PM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 17:05:19 +0100, John Keeping wrote:
In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Are you sure that it's a correct change?
IIUC, the in_ports and out_ports parameters are for external IN and OUT jacks, where an external OUT jack is connected to an embedded IN jack, and an external IN jack is connected to an embedded OUT jack.
I think it depends how the in_ports and out_ports values in configfs are interpreted. However, the case where in_ports != out_ports has been broken since these files were added!
Without this change, setting in_ports=4 out_ports=2 we end up with:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 9 baAssocJackID( 1) 11 baAssocJackID( 2) 9 baAssocJackID( 3) 0 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 2 baAssocJackID( 1) 4
Note that baAssocJackID values 2 and 3 on the OUT endpoint are wrong.
From the same config, the jack definitions are:
1: IN External 2: OUT Embedded, source 1 3: IN External 4: OUT Embedded, source 3 5: IN External 6: OUT Embedded, source 5 7: IN External 8: OUT Embedded, source 7
9: IN Embedded 10: OUT External, source 9 11: IN Embedded 12: OUT External, source 11
So it seems that the first 2 entries in each endpoint list are correct. For the OUT endpoint, jacks 9 and 11 are embedded IN jacks and for the IN endpoint, jacks 2 and 4 are embedded OUT jacks.
The problem is that the OUT endpoint lists two extra invalid jack IDs and the IN endpoint should list jacks 6 and 8 but does not.
After applying this patch, the endpoint descriptors for the same config are:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 9 baAssocJackID( 1) 11 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 2 baAssocJackID( 1) 4 baAssocJackID( 2) 6 baAssocJackID( 3) 8
Which lists all the jack IDs where they should be.
Regards, John
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com
drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) } /* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i; -- 2.48.1
On Wed, 29 Jan 2025 18:31:35 +0100, John Keeping wrote:
On Wed, Jan 29, 2025 at 05:40:04PM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 17:05:19 +0100, John Keeping wrote:
In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Are you sure that it's a correct change?
IIUC, the in_ports and out_ports parameters are for external IN and OUT jacks, where an external OUT jack is connected to an embedded IN jack, and an external IN jack is connected to an embedded OUT jack.
I think it depends how the in_ports and out_ports values in configfs are interpreted. However, the case where in_ports != out_ports has been broken since these files were added!
Without this change, setting in_ports=4 out_ports=2 we end up with:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 9 baAssocJackID( 1) 11 baAssocJackID( 2) 9 baAssocJackID( 3) 0 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 2 baAssocJackID( 1) 4Note that baAssocJackID values 2 and 3 on the OUT endpoint are wrong.
From the same config, the jack definitions are:
1: IN External 2: OUT Embedded, source 1 3: IN External 4: OUT Embedded, source 3 5: IN External 6: OUT Embedded, source 5 7: IN External 8: OUT Embedded, source 7
9: IN Embedded 10: OUT External, source 9 11: IN Embedded 12: OUT External, source 11
So it seems that the first 2 entries in each endpoint list are correct. For the OUT endpoint, jacks 9 and 11 are embedded IN jacks and for the IN endpoint, jacks 2 and 4 are embedded OUT jacks.
The problem is that the OUT endpoint lists two extra invalid jack IDs and the IN endpoint should list jacks 6 and 8 but does not.
After applying this patch, the endpoint descriptors for the same config are:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 9 baAssocJackID( 1) 11 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 2 baAssocJackID( 1) 4 baAssocJackID( 2) 6 baAssocJackID( 3) 8Which lists all the jack IDs where they should be.
Hmm, I don't get your point. The embedded IN is paired with the external OUT. That's the intended behavior, no?
Takashi
Regards, John
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com
drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) } /* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i; -- 2.48.1
On Thu, Jan 30, 2025 at 11:50:07AM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 18:31:35 +0100, John Keeping wrote:
On Wed, Jan 29, 2025 at 05:40:04PM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 17:05:19 +0100, John Keeping wrote:
In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Are you sure that it's a correct change?
IIUC, the in_ports and out_ports parameters are for external IN and OUT jacks, where an external OUT jack is connected to an embedded IN jack, and an external IN jack is connected to an embedded OUT jack.
I think it depends how the in_ports and out_ports values in configfs are interpreted. However, the case where in_ports != out_ports has been broken since these files were added!
Without this change, setting in_ports=4 out_ports=2 we end up with:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 9 baAssocJackID( 1) 11 baAssocJackID( 2) 9 baAssocJackID( 3) 0 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 2 baAssocJackID( 1) 4Note that baAssocJackID values 2 and 3 on the OUT endpoint are wrong.
From the same config, the jack definitions are:
1: IN External 2: OUT Embedded, source 1 3: IN External 4: OUT Embedded, source 3 5: IN External 6: OUT Embedded, source 5 7: IN External 8: OUT Embedded, source 7
9: IN Embedded 10: OUT External, source 9 11: IN Embedded 12: OUT External, source 11
So it seems that the first 2 entries in each endpoint list are correct. For the OUT endpoint, jacks 9 and 11 are embedded IN jacks and for the IN endpoint, jacks 2 and 4 are embedded OUT jacks.
The problem is that the OUT endpoint lists two extra invalid jack IDs and the IN endpoint should list jacks 6 and 8 but does not.
After applying this patch, the endpoint descriptors for the same config are:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 9 baAssocJackID( 1) 11 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 2 baAssocJackID( 1) 4 baAssocJackID( 2) 6 baAssocJackID( 3) 8Which lists all the jack IDs where they should be.
Hmm, I don't get your point. The embedded IN is paired with the external OUT. That's the intended behavior, no?
Yes, all the endpoint assignments are correct - when they appear in the lists!
The issue is setting bNumEmbMIDIJack and bLength in the MIDIStreaming Endpoint Descriptors. Without this patch these are set the wrong way round so either some ports do not appear or there are bogus entries containing uninitialized stack memory.
Regards, John
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com
drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) } /* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i; -- 2.48.1
On Thu, 30 Jan 2025 11:59:05 +0100, John Keeping wrote:
On Thu, Jan 30, 2025 at 11:50:07AM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 18:31:35 +0100, John Keeping wrote:
On Wed, Jan 29, 2025 at 05:40:04PM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 17:05:19 +0100, John Keeping wrote:
In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Are you sure that it's a correct change?
IIUC, the in_ports and out_ports parameters are for external IN and OUT jacks, where an external OUT jack is connected to an embedded IN jack, and an external IN jack is connected to an embedded OUT jack.
I think it depends how the in_ports and out_ports values in configfs are interpreted. However, the case where in_ports != out_ports has been broken since these files were added!
Without this change, setting in_ports=4 out_ports=2 we end up with:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 9 baAssocJackID( 1) 11 baAssocJackID( 2) 9 baAssocJackID( 3) 0 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 2 baAssocJackID( 1) 4Note that baAssocJackID values 2 and 3 on the OUT endpoint are wrong.
From the same config, the jack definitions are:
1: IN External 2: OUT Embedded, source 1 3: IN External 4: OUT Embedded, source 3 5: IN External 6: OUT Embedded, source 5 7: IN External 8: OUT Embedded, source 7
9: IN Embedded 10: OUT External, source 9 11: IN Embedded 12: OUT External, source 11
So it seems that the first 2 entries in each endpoint list are correct. For the OUT endpoint, jacks 9 and 11 are embedded IN jacks and for the IN endpoint, jacks 2 and 4 are embedded OUT jacks.
The problem is that the OUT endpoint lists two extra invalid jack IDs and the IN endpoint should list jacks 6 and 8 but does not.
After applying this patch, the endpoint descriptors for the same config are:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 9 baAssocJackID( 1) 11 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 2 baAssocJackID( 1) 4 baAssocJackID( 2) 6 baAssocJackID( 3) 8Which lists all the jack IDs where they should be.
Hmm, I don't get your point. The embedded IN is paired with the external OUT. That's the intended behavior, no?
Yes, all the endpoint assignments are correct - when they appear in the lists!
The issue is setting bNumEmbMIDIJack and bLength in the MIDIStreaming Endpoint Descriptors. Without this patch these are set the wrong way round so either some ports do not appear or there are bogus entries containing uninitialized stack memory.
OK, now point taken. The main problem here is the definition of in_port and out_ports aren't really clear. If in_ports really corresponds to external IN jacks, then we may correct rather like:
--- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -968,7 +968,7 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) midi_function[i++] = (struct usb_descriptor_header *) out_emb;
/* link it to the endpoint */ - ms_in_desc.baAssocJackID[n] = out_emb->bJackID; + ms_out_desc.baAssocJackID[n] = out_emb->bJackID; }
/* configure the external OUT jacks, each linked to an embedded IN jack */ @@ -996,7 +996,7 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) midi_function[i++] = (struct usb_descriptor_header *) out_ext;
/* link it to the endpoint */ - ms_out_desc.baAssocJackID[n] = in_emb->bJackID; + ms_in_desc.baAssocJackID[n] = in_emb->bJackID; }
/* configure the endpoint descriptors ... */
OTOH, the current code will make the actual appearance other way round, likely more confusing. So I believe your fix makes sense.
But it'd be helpful to extend the description a bit more to clarify this confusion. I guess this confusion came from the association between the embedded and external jacks, and the patch corrects it.
thanks,
Takashi
Regards, John
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com
drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) } /* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i; -- 2.48.1
On Thu, Jan 30, 2025 at 01:17:59PM +0100, Takashi Iwai wrote:
On Thu, 30 Jan 2025 11:59:05 +0100, John Keeping wrote:
On Thu, Jan 30, 2025 at 11:50:07AM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 18:31:35 +0100, John Keeping wrote:
On Wed, Jan 29, 2025 at 05:40:04PM +0100, Takashi Iwai wrote:
On Wed, 29 Jan 2025 17:05:19 +0100, John Keeping wrote:
In the two loops before setting the MIDIStreaming descriptors, ms_in_desc.baAssocJackID[] has entries written for "in_ports" values and ms_out_desc.baAssocJackID[] has entries written for "out_ports" values. But the counts and lengths are set the other way round in the descriptors.
Fix the descriptors so that the bNumEmbMIDIJack values and the descriptor lengths match the number of entries populated in the trailing arrays.
Are you sure that it's a correct change?
IIUC, the in_ports and out_ports parameters are for external IN and OUT jacks, where an external OUT jack is connected to an embedded IN jack, and an external IN jack is connected to an embedded OUT jack.
I think it depends how the in_ports and out_ports values in configfs are interpreted. However, the case where in_ports != out_ports has been broken since these files were added!
Without this change, setting in_ports=4 out_ports=2 we end up with:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 9 baAssocJackID( 1) 11 baAssocJackID( 2) 9 baAssocJackID( 3) 0 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 2 baAssocJackID( 1) 4Note that baAssocJackID values 2 and 3 on the OUT endpoint are wrong.
From the same config, the jack definitions are:
1: IN External 2: OUT Embedded, source 1 3: IN External 4: OUT Embedded, source 3 5: IN External 6: OUT Embedded, source 5 7: IN External 8: OUT Embedded, source 7
9: IN Embedded 10: OUT External, source 9 11: IN Embedded 12: OUT External, source 11
So it seems that the first 2 entries in each endpoint list are correct. For the OUT endpoint, jacks 9 and 11 are embedded IN jacks and for the IN endpoint, jacks 2 and 4 are embedded OUT jacks.
The problem is that the OUT endpoint lists two extra invalid jack IDs and the IN endpoint should list jacks 6 and 8 but does not.
After applying this patch, the endpoint descriptors for the same config are:
Endpoint Descriptor: [...] bEndpointAddress 0x01 EP 1 OUT [...] MIDIStreaming Endpoint Descriptor: bLength 6 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 2 baAssocJackID( 0) 9 baAssocJackID( 1) 11 Endpoint Descriptor: [...] bEndpointAddress 0x81 EP 1 IN [...] MIDIStreaming Endpoint Descriptor: bLength 8 bDescriptorType 37 bDescriptorSubtype 1 (Invalid) bNumEmbMIDIJack 4 baAssocJackID( 0) 2 baAssocJackID( 1) 4 baAssocJackID( 2) 6 baAssocJackID( 3) 8Which lists all the jack IDs where they should be.
Hmm, I don't get your point. The embedded IN is paired with the external OUT. That's the intended behavior, no?
Yes, all the endpoint assignments are correct - when they appear in the lists!
The issue is setting bNumEmbMIDIJack and bLength in the MIDIStreaming Endpoint Descriptors. Without this patch these are set the wrong way round so either some ports do not appear or there are bogus entries containing uninitialized stack memory.
OK, now point taken. The main problem here is the definition of in_port and out_ports aren't really clear. If in_ports really corresponds to external IN jacks, then we may correct rather like:
--- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -968,7 +968,7 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) midi_function[i++] = (struct usb_descriptor_header *) out_emb; /* link it to the endpoint */
ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
ms_out_desc.baAssocJackID[n] = out_emb->bJackID;/* configure the external OUT jacks, each linked to an embedded IN jack */ @@ -996,7 +996,7 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) midi_function[i++] = (struct usb_descriptor_header *) out_ext; /* link it to the endpoint */
ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
ms_in_desc.baAssocJackID[n] = in_emb->bJackID;/* configure the endpoint descriptors ... */
OTOH, the current code will make the actual appearance other way round, likely more confusing. So I believe your fix makes sense.
It always takes me a few minutes to get used to working in device-side USB because IN and OUT refer to the host's view.
But I think "in_ports" and "out_ports" here are consistent with that. "in_ports" are the ports that send MIDI into the USB host, and "out_ports" are the ports receiving MIDI from the USB host over an OUT endpoint.
But it'd be helpful to extend the description a bit more to clarify this confusion. I guess this confusion came from the association between the embedded and external jacks, and the patch corrects it.
I'll rewrite the commit message to include some more of this context and send a v2 later today or tomorrow.
Regards, John
Cc: stable@vger.kernel.org Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports") Signed-off-by: John Keeping jkeeping@inmusicbrands.com
drivers/usb/gadget/function/f_midi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 837fcdfa3840f..6cc3d86cb4774 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1000,11 +1000,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) } /* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */ endpoint_descriptor_index = i; -- 2.48.1
linux-stable-mirror@lists.linaro.org
-
John Keeping -
Takashi Iwai