emac_dm9051: no mem for receive buffer

[kesha.modhia]

while using ethernet in esp32 wrover I module
in between in the running network suddenly i get the below given error

emac_dm9051: no mem for receive buffer

what does that mean? how do i handle the scenario ?
have set the below macro range
ETH_MAX_PAYLOAD_LEN 1500

and the rx tx buffer sizes are as given below

CONFIG_ETH_DMA_RX_BUFFER_NUM=5
CONFIG_ETH_DMA_TX_BUFFER_NUM=5


kindly let me know the route cause that can generate the error

[ESP_ondrej]

What ESP-IDF version do you use?

[kesha.modhia]

esp-idf 4.2 I am using.

[ESP_ondrej]

This issue happens when your application consumes a lot of memory and if Ethernet messages are received with short interval. The size of packet doesn't matter since the driver always allocates 1500B. The driver was optimized in ESP-IDF v5.0 and above. I recently backported the optimization to v4.3 and v4.4 (see https://github.com/espressif/esp-idf/co ... cf549f76be). It will be present in next official release.