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Fix USB issues caused by early usb_cdc.Serial read 

Check for connected before calling read. Otherwise TinyUSB may
setup the read on the wrong endpoint.

Fixes #6018
`
This commit is contained in:
Scott Shawcroft 2022-10-21 20:42:26 -07:00
parent a4238d815d
commit eb1b2f38a0
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GPG Key ID: 0DFD512649C052DA
1 changed files with 7 additions and 2 deletions
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9
shared-module/usb_cdc/Serial.c
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@ -38,7 +38,10 @@ size_t common_hal_usb_cdc_serial_read(usb_cdc_serial_obj_t *self, uint8_t *data,
// Read up to len bytes immediately.
// The number of bytes read will not be larger than what is already in the TinyUSB FIFO.
uint32_t total_num_read = tud_cdc_n_read(self->idx, data, len);
uint32_t total_num_read = 0;
if (tud_cdc_n_connected(self->idx)) {
total_num_read = tud_cdc_n_read(self->idx, data, len);
}
if (wait_forever || wait_for_timeout) {
// Continue filling the buffer past what we already read.
@ -65,7 +68,9 @@ size_t common_hal_usb_cdc_serial_read(usb_cdc_serial_obj_t *self, uint8_t *data,
data += num_read;
// Try to read another batch of bytes.
num_read = tud_cdc_n_read(self->idx, data, len);
if (tud_cdc_n_connected(self->idx)) {
num_read = tud_cdc_n_read(self->idx, data, len);
}
total_num_read += num_read;
}
}