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stm32/otg: report the full bLength in generated string descriptors #63

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Merged
andoma merged 1 commit into from
Sep 8, 2026
Merged

stm32/otg: report the full bLength in generated string descriptors #63

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17 changes: 11 additions & 6 deletions src/platform/stm32/stm32_otg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,7 @@ typedef struct tx_ptr {
uint16_t offset;
uint16_t total;
uint8_t zlp;
uint8_t blength; // full descriptor length when generated on the fly
} tx_ptr_t;


Expand Down Expand Up @@ -205,7 +206,7 @@ read_string_as_desc(void *opaque)

switch(tp->offset) {
case 0:
r = tp->total;
r = tp->blength;
break;
case 1:
r = USB_DESC_TYPE_STRING;
Expand Down Expand Up @@ -234,7 +235,7 @@ read_bin2hex_as_desc(void *opaque)

switch(tp->offset) {
case 0:
r = tp->total;
r = tp->blength;
break;
case 1:
r = USB_DESC_TYPE_STRING;
Expand Down Expand Up @@ -379,12 +380,15 @@ handle_get_descriptor(usb_ctrl_t *uc)

case USB_DESC_TYPE_STRING:

// String 0 is the raw LANGID list, not a UTF-16 string
if(index == 0) {
desc = "\x04\x03\x09\x04";
desclen = 4;
break;
}

getch = read_string_as_desc;
switch(index) {
case 0:
desc = "\x09\x04";
desclen = 2;
break;
case 1:
desc = uc->uc_manufacturer;
desclen = strlen(desc);
Expand Down Expand Up @@ -419,6 +423,7 @@ handle_get_descriptor(usb_ctrl_t *uc)
tp->getch = getch;
tp->offset = 0;
tp->total = MIN(reqlen, desclen);
tp->blength = desclen;
tp->zlp = 0;

// If the descriptor is shorter then asked for and is a multiple of 8
Expand Down
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